JP2011511568A - Communication of transmitter identification information using positioning pilot channel - Google Patents

Abstract

  A method for communicating transmitter identification information in an interlaced structure of a communication network system using a positioning pilot channel (PPC) comprising: a) in a positioning pilot channel symbol for an active transmitter Encoding pilot information in a first portion of a plurality of subcarriers; and b) encoding transmitter identification information in a second portion of the plurality of subcarriers of the symbol, The first part of the plurality of subcarriers comprises at least a first and second interlace, the second part of the plurality of subcarriers comprises at least a third interlace, and the pilot information uses a wide area identifier in the first interlace. Scrambled and at least in the second interlace Scrambled with children and local area identifier, the method comprising at least one interlace, one or transmitter identification information of a plurality of transmitters location coordinates in the form during the free interlace.

Description

Priority claim under 35 USC 119 This patent application is assigned to the assignee of this application and is hereby expressly incorporated herein by reference. 61 / 023,919, provisional application 61 / 024,143 filed January 28, 2008, and provisional application 61 / 030,178 filed February 20, 2008 Insist.

  The present application relates generally to the operation of communication systems, and more particularly to a method and apparatus for transmitting identification information about a transmitter in a communication system.

  In currently known communication systems, such as content distribution / media distribution systems (eg, Forward Link Only (FLO) or Digital Video Broadcasting (DVB-T / H) systems), real-time and non-real-time services typically transmit frames. (E.g., FLO superframe) and delivered to devices on the network. Further, such communication systems can utilize orthogonal frequency division multiplexing (OFDM) to provide communication between a network server and one or more mobile devices. This communication provides a transmission superframe having a data slot in which content distributed over a distribution network as a transmission waveform is mounted.

  It is known to perform mobile device transmitter identification and location determination in some wireless networks by using Positioning Pilot Channel (PPC) in FLO networks. In particular, the known transmitter identification includes determining the channel profile from the pilot symbols of the active PPC symbol from the individual transmitter to the receiver. The transmitter identification information cannot be explicitly encoded in the PPC symbol, but when the transmitter transmits the active PPC symbol, such as the ordering of active transmitters in a pseudo time division multiple access (TDMA) scheme As long as the schedule is known, the identity of the transmitter in a given region can be determined (eg, if only one transmitter is active at a time in a given region, the transmitter is active Follow a known time series of simple transmissions). Thus, using the location of the active PPC symbol in the superframe and further using an overhead channel (eg, overhead information symbol (OIS)) in the superframe, the transmitter can be mapped to the corresponding PPC symbol. Is possible. Under this scheme, the periodicity (ie scheduling) of the network transmitter with respect to the superframe must also be known to the receiver.

  According to one aspect, a method for communicating transmitter identification information in a communication system is disclosed. The method encodes pilot information in a first portion of a plurality of subcarriers in a symbol for an active transmitter and transmits transmitter identification information in a second portion of the subcarriers of the symbol. Encoding.

  According to another aspect, an apparatus for communicating transmitter identification information in a network is disclosed. The apparatus includes a first module configured to encode pilot information in a first portion of a plurality of subcarriers in a symbol for an active transmitter, and a second of a plurality of subcarriers in the symbol. And a second module configured to encode transmitter identification information.

  According to yet another aspect, another apparatus for transmitting transmitter identification information in a communication system is disclosed. The apparatus includes means for encoding pilot information in a first portion of a plurality of subcarriers in a symbol for an active transmitter, and a transmitter identification in a second portion of the plurality of subcarriers in the symbol. And means for encoding the information.

  According to yet another aspect, a computer program product is disclosed. The computer program product includes a code for causing a computer to encode pilot information into a first portion of a plurality of subcarriers in a symbol for an active transmitter, and a plurality of subcarriers in the symbol. And a code for causing the computer to encode the transmitter identification information in the second portion of the computer.

  In another aspect, at least one processor is disclosed that is configured to perform a method for transmitting transmitter identification information in a network. The method encodes pilot information in a first portion of a plurality of subcarriers in a symbol for an active transmitter and transmits transmitter identification information in a second portion of the subcarriers of the symbol. Encoding.

  In a further aspect, a method for determining transmitter identification information at a device in a communication system is disclosed. The method comprises receiving at least one symbol having a plurality of subcarriers from a transmitter. The method uses a first portion of a plurality of subcarriers in at least one symbol to determine a channel estimate and an energy measurement for at least one symbol from the transmitter, and transmitter identification information Decoding the dedicated second portion of the plurality of subcarriers in the at least one symbol.

  According to yet another aspect, an apparatus for determining transmitter identification information at a device in a communication system is disclosed. The apparatus uses at least one symbol having a plurality of subcarriers from the transmitter and a first portion of the plurality of subcarriers in the at least one symbol from the transmitter, at least. Means for determining a channel estimate and an energy measurement for a symbol. The apparatus further includes means for decoding a dedicated second portion of the plurality of subcarriers in the at least one symbol to determine transmitter identification information.

  In yet a further aspect, a computer program product is disclosed. The computer program product includes a code for causing a computer to receive at least one symbol having a plurality of subcarriers from a transmitter, and a number of subcarriers in the at least one symbol from the transmitter. A computer readable medium having code for causing a computer to determine a channel estimate and an energy measurement of at least one symbol using the portion of one. The medium also includes code for causing a computer to decode a dedicated second portion of a plurality of subcarriers in at least one symbol to determine transmitter identification information.

  In yet a further aspect, when transmitter identification information is signaled in the form of transmitter location coordinates (eg, GPS position coordinates), a novel implementation for presenting and transmitting transmitter location information is described herein. Presented.

The figure which shows the communication network which can use the transmitter identification information system to disclose. The figure which shows the example of the communication system characterized by transmission of transmitter identification information. The figure which shows the transmission super-frame used in the system of FIG. 1 or FIG. FIG. 4 is a functional diagram of an interlace structure of OFDM symbols used for PPC symbols transmitted by an active transmitter. FIG. 4 is a functional diagram of an interlace structure of OFDM symbols used for PPC symbols transmitted by passive or inactive transmitters. FIG. 5 shows an apparatus for encoding transmitter identification information in an interlace of active PPC symbols, such as that shown in FIG. FIG. 3 illustrates an example hardware circuit that can be utilized at a transmitter to generate an RM code. FIG. 3 illustrates a method for providing transmitter identification information in a wireless system, such as the system illustrated in FIGS. 1 and 2. The figure which shows the apparatus for transmitting the PPC symbol which has transmitter identification information. FIG. 6 shows a method for receiving a symbol including transmitter identification information. FIG. 5 shows another example of a device for use in a receiver device or alternatively a receiver that can be used in a system having transmitter identification information.

  The present disclosure relates to a method and apparatus for transmitting identification information related to a transmitter in a communication system. The method and apparatus provide a scheme for transmitter identification and location using a PPC channel that does not require that the scheduling of the transmitter in the local network area be known to the receiver. In particular, the disclosed method and apparatus uses a PPC symbol that includes transmitter identification information so that the receiver only needs timing information and PPC symbols from the superframe to determine the identity of the active transmitter. adopt. In a particular example, the transmitter identity can be explicitly encoded in a PPC symbol. By explicitly encoding the transmitter identity in the PPC symbol, the transmitter does not need to know more advanced scheduling information of the network transmitter. However, the transmitter must perform additional processing to embed the transmitter identity information in the PPC symbol in a robust manner, and the receiver processes the PPC symbol to extract the transmitter identity information. Must. However, the transmitter identification information requires fewer processing resources that the receiver needs to use to identify the transmitter and for corresponding location using the identified transmitter's channel profile. . Further, the additional information encoded identification information can signal to the receiver whether additional symbols are being used by a particular transmitter.

  For purposes of this description, this document uses orthogonal frequency division multiplexing (OFDM) to communicate between a network transmitter and one or more mobile devices such as FLO or DVB-T / H. The transmitter identification method will be described with respect to the communication network to be used. In one example, the disclosed communication system can employ the concept of a single frequency network (SFN) where signals from multiple transmitters in the network carry the same content and transmit the same waveform. Thus, to the receiver, the waveform appears as if it were signals from the same source with different propagation delays.

  Note further that the exemplary OFDM system disclosed herein utilizes, for example, superframes. The superframe includes data symbols that are used to transport services from the server to the receiving device. According to an example, a data slot is defined as a set of a predetermined number of data symbols (eg, 500) that occur over one OFDM symbol time. Further, one OFDM symbol time in a superframe can carry 8 slots of data, by way of example only.

  According to a further example, the PPC in the superframe includes PPC symbols that are used to provide transmitter identification information about the channel estimates of individual transmitters in the network to be determined. In that case, individual for both network optimization (transmitter delay for network optimization and power profiling) and location (by measuring delay from all nearby transmitters according to triangulation techniques) Channel estimates can be used.

  In the exemplary system, the superframe boundaries at all transmitters are synchronized to a common clock reference. For example, the common clock reference is derived from the Global Positioning System (GPS) time reference. In that case, the receiving device uses PPC symbols to identify a particular transmitter and channel estimates from a set of transmitters in the vicinity of the receiving device.

  FIG. 1 illustrates a communication network 100 that can employ the methods and apparatus of the present disclosure. The illustrated network 100 includes two wide area regions 102 and 104. Each of the wide area regions 102 and 104 generally covers a large geographic area, such as a state, multiple states, part of a country, an entire country, or more than one country. Further, the wide area area 102 or 104 can include a local area area (or a sub area). For example, the wide area area 102 includes local area areas 106 and 108, and the wide area area 104 includes a local area area 110. It should be noted that the network 100 only illustrates one network configuration and other network configurations having any number of wide area regions and local area regions can be contemplated.

  Each of the local area regions 106, 108, 110 includes one or more transmitters that provide network coverage for a mobile device (eg, a receiver). For example, region 108 includes transmitters 112, 114, and 116 that provide network communication for mobile devices 118 and 120. Similarly, region 106 includes transmitters 122, 124, and 126 that provide network communication to devices 128 and 130, and region 110 is illustrated with transmitters 132, 134, and 136 that provide network communication to devices 138 and 140. Yes.

  As shown in FIG. 1, a receiving device may receive a PPC symbol from a transmitter in its local area, a PPC symbol from a transmitter in another local area within the same wide area, or a local area outside that wide area. Superframe transmissions containing PPC symbols from the middle transmitter can be received. For example, as shown by arrows 142 and 144, device 118 receives a superframe from a transmitter in its local area 108. As indicated by arrow 146, device 118 may also receive superframes from transmitters in another local area 106 in wide area 102. Device 118 can potentially further receive a superframe from a transmitter in local area 110 in another wide area 104, as shown at 148.

  "Methods and Apparatus for Position Location in a Wireless Network" by Mukkavilli et al., Filed Sep. 6, 2006, U.S. Patent Application No. 11 / 517,119, which is expressly incorporated herein by reference. As disclosed in the patent application entitled, PPC symbols transmitted by an active transmitter are configured differently from transmitters that are idle or dormant simultaneously for PPC symbol transmission. During operation, network provisioning information is used by each transmitter to determine which transmitter in the area will be the “active transmitter”.

  Note that for the purposes of this application, an active transmitter is a transmitter that transmits PPC symbols, including identification information that uses at least a portion of the subcarriers (eg, interlaces). Although only one active symbol is allocated to an active transmitter, any number of active symbols can be allocated to a transmitter. Thus, each transmitter is associated with an “active symbol” with which the transmitter transmits information including identification information. The transmitter transmits in the defined idle portion (eg, interlace) of the PPC symbol when not in the active state. In that case, the receiving devices in the network may be configured not to “listen” for information in the idle portion of the PPC symbol. This allows the transmitter to transmit in the idle portion of the PPC symbol to provide power (ie, energy per symbol) stability to maintain network performance. In a further example, symbols transmitted on the PPC are designed to have a long cyclic prefix (CP) so that the receiving device can utilize information from a distant transmitter for position determination purposes. . Since other transmitters are transmitting on the idle portion (interlace) of the symbol, this mechanism allows the receiving device to identify in its associated active symbol without interference from other transmitters in the region. It is possible to receive identification information from other transmitters.

  FIG. 2 shows an example of a communication system 200 that includes transmission of transmitter identification information (referred to herein as TxID). System 200 includes a plurality of transmitters (eg, five transmitters T1-T5) that transmit a superframe that includes a pilot positioning channel (PPC) 202 to at least one receiving device 206 via wireless link 204. . Transmitters T1-T5 represent transmitters near device 206, and may include transmitters in the same local area as device 206, transmitters in different local areas, or transmitters in different wide areas. . Transmitters T1-T5 are part of a communication network that is synchronized to a single time base (eg, GPS time) so that superframes transmitted from transmitters T1-T5 are time aligned and synchronized. Note that can be. Note that it is possible to take into account the fixed offset of the start of the superframe for a single time base and eliminate the offset of each transmitter in determining the propagation delay. Thus, the transmitted superframe content is identical to transmitters in the same local area, but unlike transmitters in different local areas or wide areas, however, the network is synchronized, so the superframe is consistent. The receiving device 206 can receive symbols from the nearby transmitter via the PPC 202 and the symbols are also matched.

  As indicated by exemplary transmitter block 214, each of transmitters T 1 -T 5 includes transmitter logic 208, PPC generator logic 210, and network logic 212. As shown by exemplary receiving device 222, receiving device 206 includes receiver logic 216, PPC decoder logic 218, and transmitter ID determination logic 220.

  Note that transmitter logic 208 may comprise hardware, software, firmware, or any suitable combination thereof. Transmitter logic 208 is operable to transmit voice, video, and network services using a transmit superframe. Transmitter logic 208 is also operable to transmit one or more PPC symbols in the superframe. In one example, the transmitter logic 208 is supervised via the PPC 202 to provide transmitter identification information used by the receiving device 222 to identify a particular transmitter, as well as for other purposes such as positioning. One or more PPC symbols 234 within the frame are transmitted.

  The PPC generator logic 210 comprises hardware, software, or any combination thereof. PPC generator logic 210 operates to incorporate transmitter identification information into symbols 234 transmitted via PPC 202. In one example, each PPC symbol comprises a plurality of subcarriers grouped into a selected number of interlaces. Interlace can be defined as a set or set of subcarriers that are evenly spaced across the available frequency band. Note that an interlace can also consist of groups of subcarriers that are not evenly spaced.

  In one example, each of the transmitters T1-T5 is allocated at least one PPC symbol called an active symbol for that transmitter. For example, transmitter T1 is assigned a PPC symbol 236 in PPC symbol 234 in the superframe, and transmitter T5 is assigned a PPC symbol 238 in PPC symbol 234 in the superframe.

  PPC generator logic 210 operates to encode transmitter identification information into active symbols for that transmitter. For example, the interlace of each symbol is grouped into two groups called “active interlace” and “idle interlace”. The PPC generator logic 210 operates to encode the transmitter identification information into a dedicated active interlace of active symbols for that transmitter. For example, transmitter T1 identification information is transmitted on the active interlace of symbol 236 and transmitter T5 identification information is transmitted on the dedicated active interlace of symbol 238. When the transmitter is not transmitting its identification information on the active symbol, the PPC generator logic 210 operates to encode the idle information into the idle interlace of the remaining symbols. For example, if the PPC 202 comprises 10 symbols, up to 10 transmitters are each assigned one PPC symbol as their respective active symbol in the SFN network. Each transmitter encodes identification information into the active interlace of its respective active symbol and encodes idle information into the idle interlace of the remaining symbols. When the transmitter is transmitting idle information on an idle interlace of PPC symbols, the transmitter logic 212 adjusts the power of the transmitted symbols to maintain a constant energy for each symbol power level. Note that it works.

  The network logic 212 is configured by hardware, software, firmware, or a combination thereof. Network logic 212 is operable to receive network provisioning information 224 and system time 226 for use by the system. Provisioning information 224 is used to determine the active symbols for each of transmitters T1-T5, where each transmitter transmits identification information on the active interlace of their active symbols. System time 226 is used to synchronize the transmissions so that the receiving device can determine the channel estimates for a particular transmitter as well as assist in propagation delay measurements.

  Receiver logic 218 comprises hardware, software, or any combination thereof. Receiver logic 218 operates to receive transmit superframes and PPC symbols 234 on PPC 202 from nearby transmitters. Receiver logic 218 operates to receive PPC symbols 234 and pass them to PPC decoder logic 220.

  The PPC decoder logic 220 comprises hardware, software, or any combination thereof. The PPC decoder logic 220 operates to decode the PPC symbols to determine the particular transmitter identity associated with each symbol. For example, the decode logic 220 operates to decode the received active interlace of each PPC symbol to determine the identity of a particular transmitter associated with that symbol. Once the transmitter identity is determined, the PPC decoder logic 220 operates to determine the channel estimate for that transmitter. For example, using a time reference associated with a received superframe, PPC decoder logic 220 may determine an active transmitter channel estimate associated with each received PPC symbol. Accordingly, the PPC decoder logic 220 operates to determine a number of transmitter identifiers and associated channel estimates. This information is then passed to position determination logic 222.

  The position determination logic 222 comprises hardware, software, or any combination thereof. The position determination logic 222 operates to calculate the position of the device 206 based on the decoded transmitter identification information received from the PPC decoder logic 220 and the associated channel estimate. For example, the location of transmitters T1-T5 is known to the network entity. Channel estimates are used to determine device distances from those locations. The position determination logic 222 then surveys the position of the device 206 using triangulation techniques.

  In operation, each transmitter 202 encodes transmitter identification information in at least one of the active interlaces of the active PPC symbol associated with that transmitter. The PPC generator logic 214 operates to determine which symbol is the active symbol for a particular transmitter based on the network provisioning information 224. When the transmitter is not transmitting its identification information on the active interlace of that active symbol, the PPC generator logic 214 causes the transmitter to transmit idle information on the idle interlace of the remaining PPC symbols. Since each transmitter is transmitting energy in each PPC symbol (ie, on either active or idle interlace), the transmitter power is not subject to fluctuations that interfere with network performance.

  When device 206 receives PPC symbols 234 from transmitters T1-T5 via PPC 202, device 206 decodes the transmitter identifier from the active interlace of each PPC symbol. Once a transmitter is identified from each PPC symbol, the device can determine the channel estimate for that transmitter based on available system timing. The device continues to determine the channel estimates for the identified transmitter until several transmitter channel estimates (ie, the preferred four estimates) are obtained. Based on these estimates, the position determination logic 222 operates to survey the device position 228 using standard triangulation techniques. In another example, the position determination logic 222 transmits the transmitter identifier and associated channel estimates to another network entity that performs triangulation or other positioning algorithms to determine the position of the device. To work.

  In one example, the positioning system, when executed by at least one processor, provides one or more program instructions (“instructions”) stored on a computer readable medium that provide the functionality of the positioning system described herein. ). For example, the instructions may be generated from PPC generator logic 214 and / or PPC decoder logic from a computer readable medium such as a floppy disk, CDROM, memory card, flash memory device, RAM, ROM, or other type of memory device. 220 is loaded. In another example, the instructions can be downloaded from an external device or network resource. When executed by at least one processor, the instructions operate to perform the example positioning system described herein.

  Thus, the positioning system operates at the transmitter to determine the active PPC symbol for which the particular transmitter transmits its identification information on the active interlace of the active PPC symbol. The positioning system also operates at the receiving device to determine transmitter channel estimates identified in the received PPC symbols and to perform triangulation techniques to determine device position.

  FIG. 3 shows a transmit superframe 300 used in either the system of FIG. 1 or FIG. As shown, each superframe 300 includes time division multiplexed (TDM) pilots (eg, TDM1 and TDM2), wide area identification channel (WIC), local area identification channel (LIC), and overhead information symbol (OIS) 302. Including head data 302, one or more data frames 304 (for example, four data frames in the example of FIG. 3), and PPC / spare symbol 306.

  According to an example, the PPC symbol can be configured such that the cyclic prefix length is increased to half the number of subcarriers, such as 2048 chips in the example of 4096 subcarrier symbols. The increased cyclic prefix allows, for example, a receiving device receiving a superframe to more appropriately eliminate channel delay spread variability. Thus, according to one example, each physical layer (PHY) PPC symbol has a duration of 6161 chips (2048 chip cyclic prefix + 4096 chips + 17 chip windows). It should be noted here that this disclosed example assumes a “4K” (ie, 4096 chip window) Fast Fourier Transform (FFT) mode. Further, according to this example, as will be described later, a Media Access Control (MAC) PPC symbol is converted into one PHY PPC symbol (i.e., "6161 chip duration with 8 interlaces per symbol" PHY PPC for 4K "FFT). However, the PPC symbol structure can be configured to be similar to the data symbol structure for the corresponding FFT mode (eg, 1K, 2K or 8K). Thus, for 1K and 2K FFT modes, the number of chips per symbol is again assumed to be, for example, 1553 chips (1024 chips + 512 cyclic prefixes), assuming a cyclic prefix equal to half the FFT window and 17 window chips, respectively. +17 window chips) and 3089 chips. The number of MAC PPC symbols in the superframe (for example, 8) is also the same as in 4K mode. It should be noted that this numerology is given as an example only and those skilled in the art will appreciate that other PPC symbol configurations and durations are possible within the scope of this disclosure.

  As can be seen from the above description, the cyclic prefix for PPC symbols in all FFT modes will be different from the data symbols. For example, the cyclic prefix in 4K FFT mode is 2048 chips, as described above, rather than the more typical 512 chips for data symbols.

FIG. 4 shows a functional diagram of an interlace structure of an OFDM symbol 400 used for PPC symbols transmitted by an active transmitter. According to an example based on the exemplary numerology described above, the symbol 400 includes 4096 subcarriers divided and grouped into 8 interlaces (I ₀ -I ₇ ) as shown, Thus, each interlace typically comprises 512 subcarriers that are not adjacent frequencies or tones. As already mentioned, it is necessary to use the receiver as follows. First, the receiving device needs to determine the channel estimate using the pilot subcarriers in the symbol. Second, the receiving device needs to determine the identity of the transmitter to which the channel estimate corresponds.

The interlace in active symbol 400 is used to transmit pilot tones as well as transmitter identification information. In the particular example of FIG. 4, the first portion of the subcarrier of symbol 400, namely interlaces I ₀ , I ₂ , I ₄ , I ₆ , labeled with reference numerals 402, 404, 406, and 408, respectively. , As well as 410, interlace I ₁ is the active interlace used to transmit pilot tones. In the case of interlaces I ₀ , I ₂ , I ₄ , I ₆ , a wide area scrambler seed (ie, a wide area differentiator) is used to ensure maximum interference suppression across the network (s). Bits (WID)) and local area scrambler seed (ie, local area differentiator bits (LID)). Furthermore, interlace I ₁ uses only the WID (eg, LID is 0 to reduce the number of hypotheses that the receiver must assume to determine WID and LID together, and therefore processing. Used by active transmitters to transmit scrambled pilots (to be set).

According to a specific example, the wide area identifier WOI ID and the local area identifier LOI ID are available in the upper layer and are actually available when the OIS symbol is decoded. At the physical layer, transmissions across various regions and sub-regions (ie wide area and local area) are distinguished by the use of different scrambler seeds (WID and / or LID). In one example, the WID is a 4-bit field that helps to separate wide area transmissions and the LID is another 4 bit field that helps to separate local area transmissions. Since there are only 16 possible WID values and only 16 possible LID values, the WID and LID values may not be unique across the network deployment. For example, a given combination of WID and LID can potentially map to multiple WOI IDs and LOI IDs. Nevertheless, network planning can be achieved so that the reuse of WID and LID is geographically separated. It is therefore possible to map a given WID and LID to a specific WOI and LOI without ambiguity in a given neighborhood. Thus, at the physical layer, the PPC waveform is designed to carry WID and LID information (ie, scrambling for interlaces I ₀ , I ₂ , I ₄ , I ₆ , and I ₁ ).

As mentioned above, an active transmitter must transmit at least 2048 pilots to allow the receiver to estimate the channel with the required delay spread. This corresponds to 4 interlaces for the active transmitter. The four active interlaces (eg, I ₀ , I ₂ , I ₄ , I ₆ ) are then scrambled using the WID and LID associated with the wide area and local area to which the transmitter belongs. Thus, the symbol receiver first extracts WID and LID information from the pilot in the active interlace of the PPC symbol and then uses the WID / LID information to obtain a channel estimate from that particular transmitter. . Also, interference from transmitters in adjacent local area networks is suppressed by scrambling using WID and LID.

However, the corresponding WID / LID identification step at the receiver can be complicated. For example, if each interlace is scrambled using both WID and LID, the receiver must detect together the WID seed and LID seed used for scrambling. There are 16 possibilities each, so that the receiver must try 256 hypotheses for joint detection. Thus, receiver detection can be simplified by allowing separate detection of WID seeds and LID seeds. Thus, in the disclosed example, the PPC waveform is separated by another group or interlace of subcarriers (eg, referenced 410) with the LID bit value set to 0000 and scrambled using only the WID value. Including interlaced I ₁ ).

In addition to the above, the apparatus and method include transmitting specific transmitter identification information stored in the PPC symbol 400 using another portion of the subcarrier. In particular, this second part of the subcarrier comprises another non-zero interlace in the PPC symbol. According to the example shown in FIG. 4, the interlace I ₃ labeled with reference numeral 412 includes transmitter identification information, but other free interlaces can also be used. This self-contained transmitter identification information allows the receiver to process the PPC independently of normal superframe processing. In particular, the transmitter identification information can be derived from PPC processing only and relies only on detection of the TDM1 pilot channel used for coarse timing detection for PPC processing. In addition, this results in a transmitter-specific PPC channel that is useful for supporting location-specific applications in a communication network, since each transmitter is provided with an essentially interference-free channel. Thus, for example, each transmitter can be configured to provide information related to a specific application, separate from mere transmitter identification information, on a transmitter specific channel. Thus, interlaces in additional PPC symbols can be utilized to carry unique application data to the receiving device.

  The specific type of information included in the transmitter identification information may initially include a transmitter identifier bit that provides a unique identifier for the transmitter. In one example, the contemplated number of bits is 18, but any suitable number of bits can be utilized. Also, additional signaling information bits can be allocated to transmitter identification information to more specifically indicate additional information to be transmitted. For example, the signaling information can be used to indicate to the receiving device whether the transmitter uses additional symbols for transmitting other information and how many additional symbols are used. In one example, the signaling information consists of 3 bits. Thus, in this example, the payload of the transmitter identification information is 21 bits (18 bits for transmitter ID + 3 bits for signaling information), but smaller or larger numbers can be contemplated.

The transmitter identification information can also include an error detection code such as a cyclic redundancy check (CRC). In one example, the CRC function can be defined using a CRC polynomial g (x) = x ⁷ + x ⁶ + x ⁴ +1, resulting in a 7-bit CRC.

Interlace I ₃ , labeled 412 (although other free interlaces may be used), transmitter identification in the form of one or more transmitter location coordinates (eg, GPS longitude, latitude, or altitude coordinates). Information can be included. Furthermore, as a possible transmitter identification indication repository, slot 3 can also contain network delay information. Note that the interlace used in transmitter location identification is also referred to herein as a slot. Accordingly, in one aspect, slot 3, i.e., the interlace I ₃ can hold the transmitter (TX) location information.

Regardless of whether transmitter identification information or other parameters are signaled in the PPC packet, one approach, Approach 1, uses a fixed bit PPC packet length of, for example, 80 bits. As a result, 10 blocks each having 8 bits are provided, and each 8 bits are converted into 100 bits. Longer payloads can be achieved compared to shorter length PPC packets. A single PPC packet size is beneficial for both testing and implementation. The packet type (field allocation) is self-contained and allows extensibility to include other parameters such as transmitter power and number of superframes. Two implementations regarding how the PPC bits are allocated are shown in Option 1 and Option 2 shown in Slide 1. Reed-Muller encoding is used in both implementations. Other variants include using the same base (64,7) Reed-Muller code, but round down to (41,7). In option 2, instead of leaving 50 bits reserved, the transmitter ID is repeated twice. Other encoding schemes are possible when generating 68 bits from an 18-bit transmitter ID.

Regardless of whether the transmitter ID information is signaled in the PPC packet, another technique, technique 2, employs a 56-bit PPC packet. 1 bit allocation is shown in Slide 2. Further attributes and benefits of Method 2 are shown in Slide 3 and Slide 4.

A third technique, technique 3, is shown in attached slides 5-8 with the exemplary format allocation shown in slide 17. For each PPC MAC time unit, each transmitter can be in one of three states: inactive, identifying, or reserved, so in technique 3, the PPC in the reserved state is Used as a transmitter-specific channel. The information includes transmitter ID information and transmitter latitude, longitude, and altitude in addition to network delay. This approach allows for a larger payload and employs turbo coding. Turbo coding provides a more robust coding compared to Reed-Muller coding for a 1000-bit payload, as shown in slide 6. As shown in slide 5, one embodiment includes four pilot slots along with three data slots. The PPC transmitter ID information and the PPC transmitter location information may be arranged in any of the data slots. Another embodiment includes 5 data slots and 2 pilot slots. There is more redundancy in the case of 5 data slots compared to 3 data slots. As further shown in FIG. 4, two interlaces or groups of subcarriers (eg, in the example of FIG. 4, interlaces I ₅ and I ₇ indicated by reference numbers 414 and 416) are idle in the active PPC symbol 400. Or zeroed. The energy in each interlace will then be (8/6) times the total OFDM symbol energy to guarantee an essentially constant power level for each OFDM PPC symbol. However, it should be noted that the power or energy allocation between the utilized interlaces (eg, interlaces I ₀ -I ₄ and I ₆ ) in active symbol 400 need not be uniform. Rather, energy can be allocated differently between different interlaces. For example, the energy of interlace I ₃ is set to 8E / 3, while the energy of interlace I ₀ , I ₂ , I ₄ , and I ₆ is set to 2E / 3, along with the energy of interlace I ₁ , in other words, The energy level of interlace I ₃ is four times greater than the energy of each of the five interlaces I ₀ , I ₁ , I ₂ , I ₄ , or I ₆ .

  Given the exemplary superframe structure described above, a superframe can support 8 transmitters in the local area using 8 PPC symbols available per superframe. However, in some deployments, the number of transmitters in the local area may be greater than eight. Furthermore, only transmitters in a specific local area are constrained to be orthogonal in time. Thus, network plans can be used to schedule transmitters on different local areas so that self-interference in the network is avoided or at least mitigated.

  Moreover, it may be desirable to support more than 8 transmitters per local area. For illustration purposes, assume that 24 transmitters are supported in the local area. To support this deployment, the network can be configured so that each transmitter transmits an active PPC symbol once every three superframes. In this case, network planning and overhead parameters can be used to inform the transmitter when each active state should occur and when identification information should be transmitted on the assigned active symbol. Thus, the periodicity of the three superframes can be programmed at the network level so that the system is scalable enough to support additional transmitters. The periodicity employed by the network can be kept constant throughout the network deployment so that both the network plan as well as the overhead information used to carry the information can be simplified. In one example, information about periodicity employed in the network is broadcast as overhead information in higher layers to allow easier programmability of this parameter. Further, if 30 PPC symbols are available per local area, the constraints on network planning to mitigate interference at the boundary of two different local areas are relaxed.

FIG. 5 shows exemplary PPC symbols transmitted by passive or inactive transmitters in the network, such as those shown in FIGS. As can be seen, the inactive PPC symbol 500 has interlaces I ₀ -I ₆ set to zero. Interlace I ₇ referenced with number 502 is the only interlace in passive transmitter symbol 500 with non-zero energy. The pilot transmitted in interlace I ₇ does not contain meaningful data or information, and the interlace can be referred to as a “dummy” interlace. According to the disclosed example, to satisfy certain OFDM symbol energy constraints, the energy in interlace I ₇ is also expanded to 8 times the energy available per OFDM symbol interlace. Transmission of passive or inactive PPC symbols 500 may be performed with active transmitter pilots, where transmissions are transmitted on interlaces I ₀ , I ₁ , I ₂ , I ₄ , and I ₆ shown in FIG. Ensure that there is no interference.

  FIG. 6 shows an apparatus 600 for encoding transmitter identification information in an interlace of active PPC symbols, such as that shown in FIG. Apparatus 600 initially includes a module 602 for setting or determining transmitter identifier (TxID) bits and allocation bits. As described above, the number of bits for TxID and allocation is set to 18 and 3, respectively. Assuming this implementation for illustration, 21 bits are passed from module 602 to module 604 configured to add CRC bits (eg, 7 bits as described above) to the TxID and allocation bits. . Module 604 then passes all bits (collectively “transmitter identification information”) to interleaver 606 (eg, block interleaver). Assuming 28 bits are passed, the block interleaver 606 can be configured as a 4 × 7 matrix in which bits are written in the column direction and correspondingly read in the row direction to achieve interleaving. . However, it should be noted that various other types of suitable interleaving for use with the devices and methods of the present disclosure can be contemplated by those skilled in the art.

  The interleaved bits are read by the encoder 608 and encoded according to a predetermined encoding method. In one example, encoder 608 may employ an RM error correction code for encoding bits, such as a primary (64,7) Reed-Muller (RM) code. In such an example, interleaver 608 passes 28 information bits to encoder 610. In the (64,7) RM code, four code blocks of 64 bits are generated from encoding of 28 information bits. However, in the specific example where 250 coded bits are desired to fit a particular numerology, the resulting 256 bits are too large. Thus, as indicated by puncture module 610 in encoder 608, two bits of the (64,7) RM code can be punctured, resulting in a (62,7) RM code. In a particular example, the bits corresponding to locations 62 and 63 in the Reed-Muller codeword can be punctured. Thus, when 28 information bits are encoded, the result is 248 encoded bits. Further, as indicated by the zero insert module 612 in encoder 608, two zeros can be added to the four code blocks to achieve 250 encoded bits. This time, the receiver assumes that the bit was 0 during decoding.

FIG. 7 shows an exemplary hardware circuit 700 that can be utilized at the transmitter to generate the RM code, more particularly within the encoder 608. As shown, the hardware circuit 700 receives a 7-bit input, indicated by an input 702 that receives input bits m ₀ -m ₆ . The circuit 700 also includes a k-1 (eg, 6) bit counter 704 that receives a clock input that increments the counter 704. The output of the counter 704 is multiplied by input bits m _{0 to} m ₅ by respective multipliers 706. Further, the most significant bit m ₆ is multiplied by a constant binary “1” value (block 708). The multiplier outputs are summed by adder block 710 to output an RM (64,7) codeword, which is a series of 64-bit values c ₆₃ -c ₀ . Note that in one example, the punctured code is obtained by deleting the values c ₆₂ and c ₆₃ .

  Returning to FIG. 6, once the transmitter information is encoded by encoder 608, repeater 614 is employed to ensure that the number of bits matches the particular numerology of the communication system. Such repetition increases the processing gain at the receiver. From the above example, if the 250 bits output by the encoder 608 are repeated four times to a total of 1000 bits, the processing gain at the receiver is 6 dB. After repeater 614 repeats the bits, the bits are scrambled, as indicated by scrambler 616. In one example, the bits can be scrambled with a seed based on a PPC symbol index (eg, 0-7 in this example) and a slot mask that is the same as the interlace index. After scrambling, modulator 618 modulates the scrambled bits for transmission according to any one of a number of modulation schemes. In the above example using 1000 bits, the bits are mapped to QPSK symbols, yielding 500 QPSK symbols. In an OFDM physical layer symbol with 4096 data subcarriers divided into 8 interlaces of 512 bits each, 500 QPSK symbols fill one interlace, which translates into a PPC symbol with 6475 chip duration. Depending on the physical layer symbol mapping, it spans one or more physical layer symbols. Those skilled in the art will appreciate that the use of repeater 614, scrambler 616, and modulator 618 is only one example of a modulation scheme, and that other suitable modulation schemes can be utilized with the disclosed methods and apparatus. Please note that.

  Furthermore, in the above example, it is assumed that the mode of the receiver has 4096 samples (ie, “4K”) Fast Fourier Transform (FFT) windows. Note that other FFT modes (eg, 1K, 2K, or 8K) are contemplated using the same method and apparatus.

  After modulation by modulator 618, the modulation symbols are interleaved by interleaver 620, for example, to mitigate frequency changes that may occur during transmission on the transmission channel. Further, depending on the FFT mode, the interlaced modulation symbols are mapped to one or more PPC physical layer (PHY) symbols. In the above example of 4K FFT mode, 500 modulated symbols are interleaved and mapped to one PHY PPC symbol. In another example of 2K FFT mode, interleaved symbols can be interleaved or even interleaved between various interlaces (within an interlace).

  FIG. 8 illustrates a method 800 for performing transmitter identification in a wireless system, such as the systems illustrated in FIGS. For example, the method 800 is suitable for use by transmitters in a network to allow a receiving device to identify a transmitter as well as determine positioning based on transmitter identification information. In one example, method 800 may be performed by a transmitter configured as illustrated at 214 shown in FIG.

  As shown, after the start of method 800, the flow proceeds to block 802 where transmitter identification information is determined. As illustrated in FIG. 2, such information is obtained from network provisioning data 224 that is transmitted to transmitter 214 as an example. Alternatively, the transmitter identification (TxID) information may be unique to the transmitter based on a prescribed network plan.

  After the TxID information is determined or retrieved, information related to whether the transmitter is active or idle for the PPC symbol is received by the transmitter as indicated by block 804. As previously described, an active transmitter transmits on the active interlace of a particular current PPC symbol, while a currently idle transmitter transmits on an idle or dummy interlace of the current PPC symbol. In one example, network logic (e.g., logic 212) in a transmitter (e.g., transmitter 214 in FIG. 2) may indicate current transmitter status from network provisioning data 224 from an appropriate network management entity or device. Receive instructions.

  At decision block 806, a determination is made as to whether the current PPC symbol transmitter is in active or idle mode. As an example, this determination is performed by the PPC generator logic 210 in the transmitter 214 shown in FIG.

If the transmitter for the current PPC symbol is active, flow proceeds to block 808 where the first portion of the subcarrier (eg, interlaced I) is scrambled with the WID seed and LID seed. ₀ , I ₂ , I ₄ , subcarriers in I ₆ ). Furthermore, as shown in block 810, by scrambling pilot with only WID seed, further portion of the first portion of subcarriers (e.g., subcarriers in interlace I ₁₎ encodes the pilots. A designated “first portion” of subcarriers is used to carry pilot tones, such as subcarriers in interlaces I ₀ , I ₂ , I ₄ , and I ₆ , and subcarriers in interlace I ₁ Note that it means a portion of the plurality of available subcarriers. Pilot coding, as indicated by blocks 808 and 810, may be performed by the transmitter logic 208 and PPC generator logic 210 shown in FIG.

As shown by block 812, to encode transmitter identification (TxID) information on a second portion of subcarriers (e.g., subcarriers in interlace I _3). As already discussed with respect to the examples of FIGS. 4, 6, and 7, the encoding of TxID information is accomplished according to a predetermined encoding scheme. The TxID encoding indicated by block 812 may be performed by the transmitter logic 208 and PPC generator logic 210 shown in FIG.

  After the TxID is encoded, a PPC symbol is transmitted as indicated by block 814. The flow then returns to block 804 for encoding of the next PPC symbol in either the same superframe or a subsequent superframe. The transmission of symbols can be performed by transmitter logic, such as logic 208, as an example.

If the current PPC symbol determined at decision block 806 is not an active symbol, the flow alternatively proceeds to block 816 as shown in FIG. In this case, idle information is encoded into a defined group of available subcarriers (eg, interlace I ₇ ) of a plurality of available subcarriers in the current PPC symbol, as indicated by block 816. As an example, this encoding may be performed by PPC generator logic 210 and transmitter logic 208. After encoding in block 816, flow proceeds to block 814 for transmission of PPC symbols.

  It is further noted that the power level of the PPC symbol can also be utilized as part of the transmission of the PPC symbol at block 814. This guarantees a constant symbol power for the SFN system, as already discussed. As an example, power adjustment may be performed by transmitter logic 208.

  Accordingly, the method 800 operates to provide a system for performing transmitter identification with PPC symbols from the transmitter. It should be noted that the method 800 represents just one embodiment and that changes, additions, deletions, combinations, or other modifications of the method 800 are possible within the scope of this disclosure. For purposes of brevity, the method of FIG. 8 is illustrated and described as a series or number of acts, some of which are in a different order than shown and described herein, and / or It should be understood that the processes described herein are not limited by the order of actions, as they are performed concurrently with other actions. For example, those skilled in the art will appreciate that a method can alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the disclosed exemplary method.

  FIG. 9 shows an apparatus for transmitting a PPC symbol having transmitter identification information. Apparatus 900 can be implemented as a transmitter, such as transmitter 214 in FIG. 2, or as a component of the transmitter. Apparatus 900 includes a module 902 that is configured to receive network provisioning data (eg, transmission status information). Module 902 communicates data related to the state of the transmitter, such as provisioning data 224 disclosed in FIG. 2, or whether the transmitter for PPC transmission is active or idle. Other suitable data or transmitter identification information (TxID) can be received. As an example of an implementation of module 902, one or more of transmitter logic 208, PPC generator logic 210, and network logic 212 may be utilized.

Apparatus 900 further includes a module 904 for encoding pilot information in a first portion of a plurality of subcarriers in a symbol of an active transmitter that uses a seed WID. As an example of a function implemented by this module, a first portion of a plurality of subcarriers is partitioned into interlace I ₁ and scrambled using a WID seed (eg, LID is set to 0000) and can do. Another module 906 for encoding transmitter identification information in a further portion of the first portion of a plurality of subcarriers of a symbol using a WID seed and a LID seed is shown in FIG. In certain implementations, module 906 may be configured to encode pilot information using subcarriers in interlaces I ₀ , I ₂ , I ₄ , and I ₆ .

Although the modules 904 and 906 are shown branched in the example of FIG. 9, the subcarriers belonging to the first part of the plurality of subcarriers, namely interlaces I ₀ , I ₁ , I ₂ , I ₄ , and I ₆ These modules can be configured as a single module for encoding pilot information. Note that as an example of an implementation of modules 904 and 906, one or more of transmitter logic 208, PPC generator logic 210, and network logic 212 may be utilized.

Apparatus 900 includes a module 908 that is used to encode transmitter identification (TxID) information into a second portion of multiple subcarriers (eg, subcarriers in interlace I ₃ ) according to a predetermined encoding scheme. In addition. Note that as an example of an implementation of modules 904 and 906, one or more of transmitter logic 208, PPC generator logic 210, and network logic 212 may be utilized.

  Apparatus 900 also includes a module 910 configured to transmit a PPC symbol that includes a coded pilot in a first portion of the plurality of subcarriers and a TxID in a second portion. Implementation of module 910 may employ transmitter logic 208, or PPC generator logic 210, or a combination thereof.

  Modules 902, 904, 906, 908, 910, and at least one processor configured to execute program instructions or code to provide aspects of the system including transmitter identification and positioning as described herein, and Note that 912 can be implemented. Further, a memory device 914 or equivalent computer readable medium for storing program instructions or code may be provided with at least one processor.

  FIG. 10 illustrates a method 1000 for receiving a symbol that includes transmitter identification information. For example, the method 1000 is suitable for use by a receiving device in a network to receive and decode PPC symbols transmitted by a currently active transmitter, such as for transmitter identification information and position determination. Yes. In one example, method 1000 can be implemented by a receiver configured as shown at 222, as shown in FIG. In addition, the method 1000 is used.

As shown, when the method is initiated for received symbols, the flow proceeds to block 1002. At block 1002, the receiver receives at least one PPC symbol. In a particular example of a 4K mode receiver, receiving at least one PPC symbol includes collecting 4096 samples of the input signal. As shown, block 1002 includes one or more of the following, such as to set an FFT scale factor and to determine an energy threshold for determining WID and LID values, as described below. It can also include measuring the energy in the interlaces. In a particular example, the energy in interlace I ₁ can be measured from the time domain interlace samples of the first received PPC PHY symbol. In addition, the energy of unused interlaces (eg, interlace I ₅ ) can be measured to determine a measure of total interference (eg, induced by heat and / or signals) on the PPC channel. In another example, hardware in a receiver, such as receiver 222, interrupts a processor, such as a digital signal processor (DSP), to program the FFT scale factor and threshold used by the hardware. Note that it is configured as follows. Setting the FFT scale factor, as an example, helps to raise the quantization noise floor of signals from weak transmitters.

The flow then proceeds to block 1004 where the WID is determined from the group of subcarriers containing pilots scrambled using only the WID, ie, interlace I _{1 as} described above. In one example, this determination can be performed by the receiver logic 216 and PPC decoder logic shown in FIG. Note that in a further example of 4K mode, a 512 point FFT can be utilized to generate frequency domain samples. In the exemplary system, WID detection is assumed to be a repeated sequence of descrambling (repeated 16 times in one exemplary system using 16 WID seeds) and an inverse FFT to produce time domain samples. Comparing the sample with an energy threshold (based on an interlaced energy measurement) and accumulating the energy value of the sample that exceeds the threshold to determine whether the WID value yields maximum energy. The WID maximum energy corresponds to the WID value.

After determining the WID value, the LID value is then determined as indicated by block 1006. Specifically, the LID is determined from a group of subcarriers including pilots scrambled using WID and LID, that is, interlace I ₀ . In one example, this determination can be performed by the receiver logic 216 and PPC decoder logic shown in FIG. Note that in a further example of 4K mode, a 512 point FFT can be utilized to generate frequency domain samples. In the exemplary system, LID detection is a repeated sequence of descrambling using the WID detected from block 1002 (repeated 16 times in one exemplary system using 16 WID and 16 LID seeds) and time domain samples. Energize these samples (based on interlaced energy measurements, such as interlaced I ₁ ) to determine which hypothesized LID value yields the maximum energy and performing an inverse FFT to yield And comparing with a threshold value. The LID maximum energy corresponds to the LID value.

Next, at block 1008, channel estimates are determined using the plurality of subcarriers encoded with the pilot. In particular, interlaces I ₀ , I ₂ , I ₄ and I ₆ are used to obtain channel estimates. In the example of a 4K mode receiver, a 512 sample FFT is performed on each of the four interlaces to obtain frequency domain samples. The sample is then descrambled using previously obtained WID and LID seeds. The descrambled pilot in the frequency domain is then input into a 2048 (2K) sample IFFT to obtain a time domain channel estimate. Once the time domain channel estimate is determined, the energy of each tap read by a processor such as a DSP is calculated and stored. In addition, the calculated energy is compared to a threshold based on previously measured energy of unused interlaces (eg, interlace I ₅ ) to determine the signal power of the currently active transmitter. Note that the procedure of block 1008 can be performed by the receiver logic 216 and PPC decoder logic shown in FIG. 2 by way of example.

Note that in a further example of a procedure for determining channel estimates assuming the above example, the 2K time domain channel estimates are aliased to the original 512 time domain points or samples. An example of an aliasing pattern is given by the following relation:

Where

Is the time domain channel estimate, s is the data interlace, and in this particular example, if each channel bin contains 512 channel taps, q is the channel bin index. Therefore, when the data interlace (s) is equal to 3, for example, the above equation (1) is as follows.

Channel estimate as given by equation (2)

Is determined, a phase ramp is applied to the time domain estimate as given by:

In order to decode the interlace, dedicated data interlace including transmitter identification information, the above example assumes that the interlace is s = 3, in other words, the interlace I ₃ including TxID given in the example of FIG. Then, to obtain a channel estimate using frequency domain samples,

Perform 512-sample FFT on.

After block 1008, flow proceeds to block 1010 where the dedicated data interlace with transmitter identification information (TxID) is decoded. As shown in FIG. 4, this dedicated interlace may be interlace I _3. As a specific example of a process for decoding at a 4K FFT mode receiver, as described above, a 512-sample FFT is performed on the aliased dedicated data interlace (I ₃ ) to obtain frequency domain samples. Can be generated. The process of block 1008 further includes generating a 1000-bit log likelihood ratio (LLR) of interlace I ₃ with QPSK modulation using the corresponding channel estimate. Next, the LLR is deinterleaved in the same manner as the deinterleaving of data symbols. After that, the 1000-bit LLR is averaged over 4 periods so that the 250-bit LLR is obtained. This averaging can be achieved, for example, according to the following relation:

Where

Represents the average LLR of the kth value. After averaging the LLRs to produce 250-bit LLRs, they are processed by a processor such as a DSP. Note that in one example, for example, averaging can be performed by hardware implemented by receiver logic 216 and / or PPC decoder logic 218. Further, the processor is encompassed by the illustrated receiver logic 216 and / or PPC decoder logic 218 shown in FIG. 2, not necessarily including only hardware logic devices.

  After the 250-bit LLR is delivered to the processor, Read Maller decoding is performed. For example, assuming the above-described exemplary encoding using RM (64,7) coding, the LLR 64-dimensional Fast Hadamard Transform (FHT) is calculated for each code block. Further, because the puncturing in the exemplary encoding described only transmits 62 bits out of 64 bits with a (64,7) RM code, the receiver has been punctured for decoding purposes. Replace bits with zeros. Thus, H is a 64 × 64 Hadamard matrix and L represents an LLR corresponding to one RM code block (ie, assuming the above example coding using 4 code blocks for 28 bits, 7 Bit), the transformation F is equal to H × L. After the transformation F is calculated, the location of the entry with the largest absolute value in the transformation F is determined. Due to the characteristics of FHT, the binary representation of the location of the largest absolute value entry gives 6 out of 7 message bits in the RM code block. The sign of the entry with the maximum absolute value gives the seventh message bit, which is 0 if the sign is positive and 1 if the sign is negative.

  After all RM code blocks containing transmitter identification information (ie, 4 RM code blocks in this example) have been decoded, a cyclic redundancy check (with high probability that the received message bits are error free) ( CRC). Then, if the CRC matches, the receiver uses the transmitter identification information and the WID, LID, and power measurements.

  The receiving device then uses the transmitter data in the transmitter identification information to identify the transmitter that originated the active PPC symbol, as shown in block 1012. Since the PPC symbol contains self-contained transmitter identification information, the receiving device needs to perform additional processing to identify the transmitter, thereby providing quick and efficient transmitter identification. In addition, this information is used in conjunction with one or more of channel estimate, WID, LID, and power measurement information, such as by triangulation or any other suitable technique, by the transmitter (s). Note that positioning information about the receiving device for can be determined.

  After the process of block 1012, flow proceeds to decision block 1014. A determination is made whether additional or further PPC symbols are indicated from the signaling information in the transmitter identification information. If no additional symbols are shown, process 1000 ends. Alternatively, if additional symbols are indicated, flow proceeds from block 1014 to block 1016 for further decoding of the additional symbols. Note that this processing can be accomplished in a manner similar to the process described above with respect to one or more of blocks 1002-1008.

It should be noted that processes for decoding other FFT mode symbols at the receiver device are also contemplated. For example, assuming a 2K FFT mode, the receiving device collects 2K samples from each symbol. A 256 point FFT is then performed for each time domain interlaced sample in the symbol. The frequency domain interlaced samples from the 256 point FFT are then concatenated with samples from two symbols (eg, PHY symbols). As an example, a set of 256 interlaced samples from the first symbol is Y ₀ = {y _0,0 , y _1,0 , y _2,0,. . . , Y _255,0 }, and a set of 256 interlaced samples from the second symbol is Y ₁ = {y _0,1 , y _1,1 , y _2,1,. . . , Y _255,1 }, the concatenation obtained from the two sets of these samples is Y = {y _0,0 , y _1,0 , y _2,0,. . . , Y _255,0 , y _0,1 , y _1,1 , y _{2,1 ,.} . . , Y _2551,1 }. After concatenating 512 samples from multiple PHY symbols, WID and LID detection, channel estimation, and LLR generation are similar to the 4K FFT operating mode processing described above with respect to one or more of blocks 1002-1016.

  In another example of 1K FFT mode, a 128-point FFT is performed on the time domain interlaced samples from each PHY PPC symbol. Similar to the above example, the frequency domain samples obtained from four PHY PPC symbols are concatenated to form one interlace. Note that in yet another example of 8K FFT mode, one interlace consists of 1000 subcarriers. Thus, the processing by the receiving device utilizes 1K FFT / IFFT processing as well as 4K IFFT processing for channel estimation.

  In this manner, method 1000 operates to allow symbols including transmitter identification information to be received and processed at a receiving device. It should be noted that the method 1000 represents just one embodiment and that changes, additions, deletions, combinations, or other modifications of the method 1000 are possible within the scope of this disclosure. For the sake of brevity, the method of FIG. 10 is illustrated and described as a series or as a number of acts, some of which are in an order different from that shown and described herein, and / or It should be understood that the processes described herein are not limited by the order of actions, as they are performed concurrently with other actions. For example, those skilled in the art will appreciate that a method can alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with the disclosed exemplary method.

FIG. 11 illustrates another example of a device for use in a receiver apparatus or alternatively in a receiver 1100 that can be used in a system having transmitter identification information. Apparatus 1100 receives at least one PPC symbol and module 1102 for determining energy in one or more interlaces, such as an interlace to use (eg, I ₁ ) and an unused interlace (eg, I ₅ ). including. In that case, the energy determination is shared with other modules in the device 1100, as indicated by the connection to the communication bus 1104. It should be noted that this bus architecture is exemplary only and indicates that various communications are possible between modules within device 1100.

Apparatus 1100 also includes a module 1106 for determining a WID seed from a predetermined interlace (eg, interlace I ₁ ). As previously described, WID determination may include thresholding based on previously measured energy, such as module 1102. The WID determined by module 1106 is passed to module 1108 for determining the LID from a predetermined interlace (eg, interlace I ₀ ) using the WID. Also, the LID detection by the module 1108 can use the measured energy determined by the module 1102.

Apparatus 1100 further includes a module 1110 for determining channel estimates from active interlaces (eg, interlaces I ₀ , I ₂ , I ₄ and I ₆ ). As previously described, determining a channel estimate may include comparing a tap energy calculation to an energy threshold, such as that determined by module 1102, for example. A module 1112 for decoding a dedicated interlace (eg, I ₃ ) is also included to determine that transmitter identification information (TxID) is further included. As an example, module 1112 may implement the decoding process detailed above in the description of block 1010 with respect to FIG. Further, a module 1114 is provided in apparatus 1100 for determining transmitter identity (and receiver device positioning based on transmitter ID, channel estimate and energy measurement) based on TxID. Module 1114 performs a cyclic redundancy check so that the received message bits are error free, and if there are no errors, processor 1116, which can be a DSP or other suitable processor (s), etc. A feature may be included that triggers an implementation in the transmitter ID table in the receiving device 1100 along with transmitter identification information, WID, LID, and measured power for use. The transmitter ID table may be included in the memory device 1118 that is in communication with the processor 1116 and / or modules in the device 1100.

  Modules 1102, 1106, 1108, 1110, 1112, and 1114 are at least one configured to execute program instructions to provide an example of a system that includes transmitter identification information and positioning as described herein. Note that it can be implemented by a processor. In one example, modules 1102, 1106, 1108, 1110, and 1112 can be implemented by receiver logic 216 and / or PPC decoder logic 218. In one example, module 1114 is implemented by position determination logic 222. Further, a memory device 1118 or equivalent computer readable medium for storing program instructions or code may be provided with at least one processor.

  Various exemplary logic, logic blocks, modules, and circuits described with respect to the disclosed examples may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or others. Note that can be implemented or performed using any programmable logic device, individual gate or transistor logic, individual hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor can be implemented as a combination of computing devices, for example, as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors associated with a DSP core, or any other such configuration.

  The method or algorithm steps or processes described with respect to the examples disclosed herein may be implemented directly in hardware, implemented in software modules executed by a processor, or a combination of the two. . A software module resides in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or other form of storage medium known in the art. be able to. An exemplary storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium can reside in the ASIC. The ASIC can reside in the user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

  The description of the disclosed examples is provided to enable any person skilled in the art to make or use the disclosed methods and apparatus. Various modifications to these disclosed examples will be readily apparent to those skilled in the art, and the general principles defined herein may be used without departing from the spirit or scope of the present disclosure (eg, It can be applied to other examples (in instant messaging services or any common wireless data communication application). Accordingly, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. The word “exemplary” is used herein exclusively to mean “serving as an example, instance, or illustration”. Any example described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other examples.

  Thus, while examples of communication systems having transmission identification information have been illustrated and described herein, it will be appreciated that various changes can be made to the examples without departing from their spirit or essential characteristics. .

Claims (43)

A method for communicating transmitter identification information in an interlaced structure of a communication network system using a positioning pilot channel (PPC), comprising:
a) encoding pilot information in a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter;
b) encoding transmitter identification information in a second part of a plurality of subcarriers of the symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least third interlaces;
The pilot information is scrambled using a wide area identifier in the first interlace, and scrambled using the wide area identifier and a local area identifier in the at least second interlace;
The method wherein at least one of the interlaces includes the transmitter identification information in the form of one or more transmitter location coordinates during free interlace.   The method of claim 1, wherein the transmitter identification information is encoded at least in the third interlace.   The method of claim 1, wherein the interlace structure is grouped into eight interlaces.   The method of claim 3, wherein the transmitter location coordinates are longitude, latitude, and / or altitude coordinates.   The method of claim 4, wherein the transmitter location coordinates of longitude, latitude and / or altitude are in interlace 3.   The method of claim 5, wherein the interlace 3 also includes network delay information.   7. The method of claim 6, wherein a fixed bit PPC packet length of 80 bits is used to provide 10 blocks of 8 bits each, each 8 bits being converted to 100 bits. As an option to the 80-bit PPC packet,

8. The method of claim 7, wherein: As an option to the 80-bit PPC packet,

8. The method of claim 7, wherein:   9. The method of claim 8, wherein the packet type further comprises parameters of transmitter power and superframe number.   The method of claim 9, wherein the packet type further comprises parameters of transmitter power and superframe number. Encoding the transmitter identification information;
Interleaving the information bits of the transmitter identification information;
Encoding the bits using a predetermined encoding scheme;
Manipulating the coded bits so that the number of bits matches a predetermined modulation scheme;
Modulating the bit according to the predetermined modulation scheme;
2. The method of claim 1, comprising mapping the modulated bits to subcarriers in the second portion of the plurality of subcarriers of the symbol.   The method of claim 12, wherein the predetermined encoding scheme comprises Reed-Muller encoding.   The method of claim 12, wherein manipulating the encoded bits includes puncturing one or more encoded bits and replacing the punctured encoded bits with a zero value.   The method of claim 12, wherein the predetermined modulation scheme comprises QPSK modulation.   The method of claim 1, wherein the communication system comprises an OFDM communication system. An apparatus for communicating transmitter identification information in an interlaced structure of a communication network system using a positioning pilot channel (PPC), comprising:
a) a first module configured to encode pilot information in a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter;
b) a second module configured to encode transmitter identification information in a second portion of the plurality of subcarriers of the symbol;
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least third interlaces;
The pilot information is scrambled using a wide area identifier in the first interlace, and scrambled using the wide area identifier and a local area identifier in the at least second interlace;
The apparatus wherein at least one of the interlaces includes the transmitter identification information in the form of one or more transmitter location coordinates during free interlace.   18. The apparatus of claim 17, wherein the first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least third interlaces. .   The apparatus of claim 17, wherein the interlace structure is grouped into eight interlaces.   The apparatus of claim 17, wherein the transmitter location coordinates of longitude, latitude and / or altitude are in interlace 3.   21. The apparatus of claim 20, wherein interlace 3 also includes network delay information.   The apparatus of claim 21, wherein 10 blocks each of 8 bits are provided, including a fixed bit PPC packet length of 80 bits, each 8 bits being converted to 100 bits. As an option to the 80-bit PPC packet,

23. The apparatus of claim 22, wherein: As an option to the 80-bit PPC packet,

23. The apparatus of claim 22, wherein: A code for causing a computer to encode pilot information into a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter;
A computer program product comprising a computer readable medium comprising code for causing a computer to encode transmitter identification information in a second portion of a plurality of subcarriers of the symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least third interlaces;
The pilot information uses a code for causing a computer to scramble using a wide area identifier in the first interlace, and uses the wide area identifier and the local area identifier in the at least second interlace. And code for causing the computer to scramble,
At least one of the interlaces includes code for causing a computer to encode the transmitter identification information in the form of one or more transmitter location coordinates in a free interlace;
Computer program product.   26. The computer program product of claim 25, wherein the transmitter identification information is encoded at least in the third interlace.   26. The computer program product of claim 25, wherein the transmitter identification information includes at least one of a transmitter identification information field, a transmitter allocation field, and a cyclic redundancy check bit.   28. The computer product of claim 27, wherein the transmitter allocation field is configured to communicate whether subsequent symbols containing additional data are transmitted.   The computer readable medium transmits transmitter allocation data in the transmitter identification information indicating allocation of one or more subsequent symbols for a transmitter specific channel used to communicate additional data. 26. The computer program product of claim 25, further comprising code for causing a computer to do. The computer readable medium is
A code for interleaving information bits of the transmitter identification information;
A code for encoding the bits using a predetermined encoding scheme;
A code for manipulating the encoded bits so that the number of bits matches a predetermined modulation scheme;
A code for modulating the bit according to the predetermined modulation scheme;
26. The computer program product of claim 25, further comprising code for mapping the modulating bits to subcarriers in the second portion of the plurality of subcarriers of the symbol.   The computer program product of claim 30, wherein the predetermined encoding scheme comprises Reed-Muller encoding.   The code for manipulating the encoded bits further comprises a code for puncturing one or more encoded bits and replacing the punctured encoded bits with a zero value; 32. The computer program product of claim 30.   32. The computer program product of claim 30, wherein the predetermined modulation scheme comprises QPSK modulation.   26. The computer product of claim 25, wherein the communication system comprises an OFDM communication system. A computer readable medium implementing a method for communicating transmitter identification information in an interlaced structure of a communication network system using a positioning pilot channel (PPC), the method comprising:
a) encoding pilot information in a first portion of a plurality of subcarriers in a positioning pilot channel symbol for an active transmitter;
b) encoding transmitter identification information in a second part of a plurality of subcarriers of the symbol,
The first portion of the plurality of subcarriers comprises at least first and second interlaces, and the second portion of the plurality of subcarriers comprises at least third interlaces;
The pilot information is scrambled using a wide area identifier in the first interlace, and scrambled using the wide area identifier and a local area identifier in the at least second interlace;
A computer readable medium wherein at least one of the interlaces includes the transmitter identification information in the form of one or more transmitter location coordinates during free interlace.   36. The computer readable medium of claim 35, wherein the transmitter identification information is encoded at least in the third interlace.   36. The computer readable medium of claim 35, wherein the interlace structure is grouped into eight interlaces.   38. The computer readable medium of claim 37, wherein the transmitter location coordinates are longitude, latitude, and / or altitude coordinates.   39. The computer readable medium of claim 38, wherein the transmitter location coordinates of longitude, latitude and / or altitude are in interlace 3.   40. The computer readable medium of claim 39, wherein interlace 3 also includes network delay information.   41. The computer readable medium of claim 40, wherein a fixed bit PPC packet length of 80 bits is used to provide 10 blocks of 8 bits each, each 8 bits being converted to 100 bits. As an option to the 80-bit PPC packet,
42. The computer readable medium of claim 41, wherein: As an option to the 80-bit PPC packet,

42. The computer readable medium of claim 41, wherein:

Images