HK1108531A - Initial pilot frequency selection - Google Patents

Description

Initial pilot frequency selection

Technical Field

The present invention relates generally to data communications, and more particularly to a system and method for selecting an initial pilot frequency for a wireless communication system.

Background

For humans, communication is always of paramount importance. Prior to the advent of modern technology, people have long begun to use human-generated sound waves to convey information. However, such communication is severely restricted by the human lung capacity. To solve this problem, a sound wave generating device (e.g., a drum) is used instead of a human voice to increase a communication distance. However, when the distance between the two parties is too far and the human ear cannot hear the sound waves, the communication fails. Thus, through technological advances, mankind has taken a great step to overcome this limitation. In one solution, sound waves are converted into electricity, which is then transmitted over wires to a destination where the electricity is converted back into sound waves. A telephone is an example of such a technology.

Although this solution greatly increases the communication distance, it also presents an additional related problem, namely the need for wires to carry electrical signals between communication points. The cost of the wires is often high and a large number of wires are required to cover a remote distance to cope with the increasing number of users. Some techniques have attempted to solve some of these problems by developing fiber optic cables that are capable of transmitting light pulses rather than electrical current. In so doing, the cabling required to transmit the same amount of communication signals is significantly reduced. However, optical fiber is more expensive, with significantly increased maintenance costs, and requires a higher level of skill to maintain the fiber optic network.

While the first thought of "communication" was human interaction, the advent of the computer age has also thought of connecting computers together. Not only is a communication network required to transmit human voice, but also information consisting of digitized data (data converted into 1 and 0) is required to be transmitted. Indeed, some techniques even digitize human voice in order to more effectively transmit it over greater distances. This requirement greatly increases the workload of a typical communications network, resulting in a significant increase in the number of wires or cables.

One seemingly obvious way to solve the above-mentioned problems of a large number of wired communication networks is to abandon the wires and use "wireless" communication systems. Although this approach appears to be very easy, developing wireless communication techniques is often a very complex problem. Early wireless communication technologies, such as radio broadcasting, enabled remote areas to receive broadcast signals from remote locations. This "one-way" communication is an unobtrusive means of information dissemination, such as announcements and news. However, it is often desirable to have two-way communication, even more so than two-way communication. In other words, people wish to have a "conversation" between two or more parties, whether they are human or electronic devices. This greatly increases the complexity of the wireless signals required to communicate effectively.

As wireless technology is introduced into telephones, the absolute number of parties wishing to communicate wirelessly has also increased dramatically. Wireless telephones have evolved into multifunctional devices for relaying voice communications as well as data communications. Some devices also incorporate an interface to the internet in order for the user to browse the world wide web and even allow the user to download/upload files. Thus, these devices have been converted from single voice devices to "multimedia" devices, allowing users to transceive not only voice information, but also image/video information. All of these additional types of media have dramatically increased the demand for communication networks that support these media services. Wherever people or devices are located, it is attractive to be able to "connect" anywhere and anytime, and the growth in network demand continues to be facilitated.

Therefore, the "air radio wave" transmitting the radio signal becomes very crowded. Complex signals are used in order to make maximum use of the signal frequency. However, due to the large number of communicating entities, it is often not sufficient to prevent the signals from "colliding". When a collision occurs, the receiver cannot interpret the signal correctly and may lose the information associated with the signal. This problem severely reduces the efficiency of the communication network, requiring multiple transmissions before the information is correctly received. In the worst case, if retransmission is not possible, the data is lost completely. If the network has hundreds or thousands of users, the probability of signal collisions increases significantly. The demand for wireless communication is not, and does not drop. It is therefore reasonable to assume that signal collisions will also increase, thereby reducing the availability of the prior art. A communication system that can avoid such data loss will be able to improve reliability and efficiency for its users.

Disclosure of Invention

A brief description is given below to assist in understanding some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key/critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

Embodiments of the systems and methods described herein relate generally to data communications using OFDM and, more particularly, to systems and methods for selecting an initial set of pilot subcarrier frequencies for a wireless communication system.

In one aspect, a method of supporting data communications includes obtaining a pilot staggering sequence of pilot signals; and shifting an order of the pilot staggering sequence to reduce collision of the pilot signal with other pilot signals.

In one embodiment, the randomized starting subcarrier frequency set of the pilot signal is used in a first Orthogonal Frequency Division Multiplexing (OFDM). In another embodiment, the number of start pilot subcarrier frequency sets is determined by using a random number generator, such as a pseudo-noise (PN) sequence generator, seeded with a communication system parameter, such as a network Identification (ID) number. Thus, the starting subcarrier frequency set is specific to this particular network. Thus, a plurality of network systems can reliably communicate, the probability of pilot signal interference is sufficiently reduced, and reception quality and coverage are improved. These embodiments also provide a more scalable system, allowing system bandwidth to be traded off for coverage area. One embodiment is a data communication method that obtains a pilot staggering sequence for pilot signals and shifts the order of the pilot staggering sequence to reduce collision of the pilot signals with other pilot signals. Another embodiment is a data communication system that employs a receiving component that receives at least one pilot staggering sequence for at least one pilot signal and a sequence determining component that shifts the order of the pilot staggering sequence to reduce the probability of collision of the pilot signal with other pilot signals.

For the purposes of the foregoing and related ends, certain illustrative embodiments of the invention are described herein in connection with the following description and the annexed drawings. These embodiments are illustrative of the various ways in which the invention can be used and the invention includes all such embodiments and their equivalents.

Drawings

Fig. 1 is a block diagram of a data communication support system according to an embodiment of the present invention;

fig. 2 is another block diagram of a data communication support system in one embodiment of the present invention;

fig. 3 is still another block diagram of a data communication support system in one embodiment of the present invention;

FIG. 4 is a block diagram of a data communication support system interfacing with a plurality of entities in one embodiment of the invention;

FIG. 5 is a schematic diagram of a network coverage area in one embodiment of the invention;

FIG. 6 illustrates national and local frame interleaving in one embodiment of the invention;

FIG. 7 is an example of a pilot stagger mode in one embodiment of the invention;

FIG. 8 illustrates a randomized pilot frequency interleaving structure in one embodiment of the invention;

FIG. 9 is a flow chart of a method of supporting data communications in one embodiment of the invention;

FIG. 10 is another flow diagram of a method of supporting data communications in one embodiment of the invention; and

fig. 11 illustrates an example of a communication system environment in which the present invention can function.

Detailed Description

The present invention is described below with reference to the attached drawings, wherein like reference numerals are used to refer to like elements. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing these embodiments. As used in this application, the term "component" is intended to refer to an entity, either hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a processor, a process running in a processor, and/or a multiplexer and/or other signal support devices and software.

In accordance with these embodiments and their disclosure, various aspects are described in connection with a subscriber station. A subscriber station can also be called a system, a subscriber unit, mobile station, mobile, remote station, access point, base station, remote terminal, access terminal, user agent, or user device. The subscriber station may be a wireless telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device having wireless connection capability, or other processing device connected to a wireless modem.

Systems and methods are provided for reducing pilot interference between a plurality of wireless networks, which are particularly well suited for supporting multimedia communication systems that typically have extremely dense and complex communication signals within a given transmission area. The communication system utilizes pilot signals to support the proper reception of communication data. For example, they can assist in the detection of the carrier signal and/or the gain control setting. Generally, the pilot signal contains predetermined data that allows the communication system to adjust itself to this reference data. By shifting the starting state of the pilot staggering sequence, the probability of collision among pilot signals of different networks can be effectively reduced, and thus the important signals can be correctly received.

The translation may be done in the first symbol of a frame of, for example, an OFDM-based system. In one embodiment, a PN sequence generator may be seeded with a communication system parameter, such as a network ID, to determine the starting state of the pilot staggering sequence, supporting order shifting. This can reduce the probability of pilot collision between different networks, greatly improve the overall efficiency of the wireless system, and improve reception quality and/or coverage. These embodiments also provide a more scalable system in which bandwidth can be reduced to increase coverage. Thus, the system can be optimized according to the needs, and the constantly changing system requirements can be met.

Communication systems are widely deployed to provide various communication services such as voice, packet data, and so on. These systems may be time, frequency and/or code division multiple access systems capable of supporting simultaneous communication with multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, multi-carrier CDMA (MC-CDMA), wideband CDMA (W-CDMA), High Speed Downlink Packet Access (HSDPA), Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

The embodiments are used with OFDM based communication systems and the like. Thus, knowledge of these systems can aid in understanding the application of the present invention. OFDM, or multi-carrier modulation, employs multiple subcarriers to communicate data between systems. High speed serial data is divided into a plurality of lower rate sub-signals that the system can simultaneously transmit in parallel at different frequencies. This allows for high spectral efficiency, radio frequency interference immunity, and less multipath distortion. The OFDM orthogonality property allows subcarriers to overlap, thus improving spectral efficiency. Therefore, OFDM-based wireless systems are able to meet the large bandwidth requirements of various applications, such as multimedia applications used in highly saturated radio frequency regions.

In one wireless standard, the OFDM physical layer distributes data signals into 52 separate subcarriers to transmit data at different rates. A group of symbols or "frame" is transmitted in each subcarrier. These symbols include the data bits that need to be transmitted. Typically, four of the subcarriers are pilot subcarriers used by the system as a reference to reduce signal frequency and/or phase offsets during transmission. Each transmitting network within the system is required to transmit pilot subcarriers to facilitate proper reception and interpretation of the transmitted data. The pilot subcarriers are always present regardless of whether pilot information is being transmitted. However, the remaining subcarriers may be used to transmit data, which may or may not include data, depending on system requirements. In general, a preamble frame is transmitted that contains multiple symbols so that a receiver can interpret it and utilize it to facilitate acquisition of the incoming OFDM signal, synchronizing its demodulator. In this way, the gain control and process carrier signal frequency can be determined and fine tuned to train the receiver. It is noted that the above is just one example, as there is no single industry standard, and both proprietary and non-proprietary standards.

The pilot signal is typically composed of a staggered sequence of subcarrier frequency groups (for improved resolution) that form a "pilot staggered sequence". One preferred embodiment of such a set of subcarrier frequencies is referred to as "interleaving". That is, the subcarriers of an OFDM symbol are subdivided into I interlaces indexed from 0 to I-1. Each interlace consists of P subcarriers, which are separated in frequency by I x Δ f, where Δ f is the subcarrier spacing. Thus, if there are, for example, 8 interlaces, the set of leading interlaces may include 8 staggered interlaces in any order selected from these 8 interlaces. Although this interleaving may change at any given time, the order of change or spread remains the same. This means that if two networks are using the same pilot stagger sequence, they will change, or "hop", to a given interlace frequency at substantially the same time. Thus, despite changing the interlaces in the pilot staggering sequence, the two networks still interfere with the pilot signal of the other. Thus, a means is provided to reduce signal interference by changing the starting interlace of the pilot stagger sequence. This approach allows pilot staggering to be staggered as before, but increases the probability of staggering the stagger to lose synchronization with a network operating with the same pilot staggering sequence.

As shown in fig. 1, a block diagram of a data communication support system 100 in one embodiment is shown. The communication support system 100 includes a pilot staggering sequence determining component 102. It 102 receives a spread sequence input 104 and provides a spread sequence output 106 that has been enhanced to reduce pilot interference. The pilot staggering sequence determining component 102 may also utilize optional data system information 108 to help determine the staggering sequence output 106. In this way, communication system parameter data specific to a particular network may be employed, making the staggering sequence output 106 substantially unique to that network.

For example, if the staggered sequence consists of interlaces 2, 1, 5 and 6, the possible starting interlace selection is limited to four interlaces of this staggered sequence. This allows four networks to have different starting interlaces, i.e., 2, 1, 5 or 6, which can substantially reduce pilot interference. Since the stagger sequence pattern remains the same but the initial stagger is changed, the stagger sequence between networks is out of synchronization, greatly increasing the probability that a pilot signal can be received without interference. The random selection of starting sequences from the small staggered sequences is likely to cause redundancy in the initial starting interlaces as the number of networks increases. Thus, the probability of signal collision naturally increases for networks employing the same ragged sequence pattern. This probability can be reduced by increasing the number of interlaces in the staggered sequence, thus reducing the likelihood that two networks will use the same starting interlace. This probability can be further reduced by using parametric data specific to the network. This is done to correlate the start sequence with a particular network and/or group of networks, thereby reducing the probability that two networks have the same start-staggered and staggered sequence.

Referring to fig. 2, another block diagram of a data communication support system 200 in one embodiment of the present invention is described. The data communication support system 200 includes a pilot staggering sequence determining component 202. The pilot staggering sequence determining component 202 includes a sequence receiving component 204, an initial staggering determining component 206, and a staggering sequence regenerator 208. The sequence receiving component 204 receives the initial pilot staggering sequence 210 and passes it 210 to the initial interlace determining component 206. Initial interlace determining component 206 determines a new starting interlace number based on initial pilot stagger sequence 210. Initial interlace determining component 206 can also utilize optional network information 214 to determine a new starting interlace number. The stagger sequence regenerator 208 receives the new start interlace number and the initial pilot stagger sequence 210, and generates a reinitialized pilot stagger sequence 212 using the new start interlace number. Those skilled in the art will appreciate that some of the functionality of the guided stagger sequence determination component 202 can reside in other components. Thus, for example, the sequence receiving component 204 may be external to the pilot staggering sequence determining component 202 and/or incorporated directly into the initial staggering determining component 206.

If, for example, the initial pilot staggering sequence 210 is (2, 4, 3, 0, 1) and the initial interlace determining component 206 selects the new starting interlace number as 3, then the possible reinitialized pilot staggering sequence may be (3, 0, 1, 2, 4). Selection 3 may be a random process by initial interlace determination component 206 and/or it may be a random process biased with network information 214 and/or a predetermined offset value based on network information 214. For example, a particular net may be defined as an even number of starting interlaces, thus reducing the number of random choices. Network information 214 may include, but is not limited to, a network identifier, network bandwidth, and/or other network specific and/or non-specific information. Thus, the predetermined offset value may be based on the network information 214 to affect the new start stagger number. For example, the network ID may be normalized and offset by, for example, 2. If the network ID increases by a multiple of 100, there will be a set of networks with IDs: 100. 200, 300, etc. For these networks, the normalized values may include 1, 2, and 3. This value can then be offset in this example such that the first network has an interlace start position of (1+2) ═ 3, the second network has an interlace start position of (2+2) ═ 4, and the third network has an interlace start position of (3+2) ═ 5, and so on. If the initial pilot staggering sequence 210 is, for example, (2, 1, 0, 5, 7, 6, 4, 3), then the first network sequence starts with an interlace at position 3 in this sequence, so the new sequence is (0, 5, 7, 6, 4, 3, 2, 1). Similarly, for the second network, the new sequence is (5, 7, 6, 4, 3, 2, 1, 0), and for the third network, the new sequence is (7, 6, 4, 3, 2, 1, 0, 5). Similar ordering of new sequences can be achieved by accumulating for each new network regardless of the network-specific ID (e.g., with 0 offset). It will be appreciated by those skilled in the art that the flexibility of the present invention allows for several additional ways to influence the choice of starting cross number and thus fall within the scope of the present invention.

Turning to fig. 3, another block diagram of a data communication support system 300 in one embodiment of the invention is shown. The data communication support system 300 includes an initial interlace determining component 302. Initial interlace determining component 302 includes a pseudo-noise (PN) sequence generator 304, which generator 304 receives interlace sequence information 306 and provides random initial interlaces 308. The pseudo-noise sequence generator can accept network information such as an optional network ID 310. This allows the random selection process provided by the pseudo-noise sequence generator 304 to be seeded by network-specific information, reducing the probability that any two networks will use the same starting cross-number as their pilot, substantially reducing pilot interference. The random initial interlaces 308 can be used by the communication system to enhance their pilot staggering sequences to reduce pilot signal interference.

Turning to fig. 4, a block diagram of a data communication support system 400 interfacing with a plurality of entities in one embodiment of the present invention is shown. The data communication support system 400 includes a pilot staggering sequence determination component 402 and entities 1-N404-408, where N represents an integer from 1 to infinity. The entities 1-N404-408 may include, but are not limited to, networks and the like. In this embodiment, the pilot staggering sequence determination component 402 generates and specifies pilot staggering sequences for the entities 1-N404-408. The generated sequence may include a biased random sequence, a predetermined offset sequence, and/or a combination of the two. In this manner, pilot signal interference can be substantially reduced because the pilot staggering sequence determination component 402 can attempt to eliminate any pilot staggering sequences that conflict between entities 1-N404-408. The pilot midamble determination component 402 can reside outside of the entities 1-N404-408 and/or inside one or more of the entities 1-N404-408. The communications between the pilot staggering sequence determination component 402 and the entities 1-N404-408 may include, but are not limited to, wireless communications and/or wired communications.

A separate embodiment of the pilot staggering sequence determination component 402 utilizing predetermined sequence offsets can also reside in multiple entities 1-N404-408. Thus, the pilot stagger sequence can be enhanced with a predetermined starting interlace offset in a known and predictable manner to mitigate pilot signal limitations. This can reduce preferred pilot interference even if communication between the pilot staggering sequence determining component 402 and other possible interfering entities is not feasible.

For OFDM broadcast systems, it is assumed that the transmitters are distributed over a wide geographical area, such as the continental united states, with a typical spacing of about 60 km. Transmitting in the lower 700MHz (vhf) band with a 6MHz radio bandwidth can be divided into two categories: (a) nationwide, which is common for wide coverage areas, (b) local, which is common in sub-areas. Thus, since the content belonging to different networks differs between different transmitters, adjacent transmissions do not interfere with each other.

The above is illustrated in fig. 5, where fig. 5 depicts an example of a network topology 500. Two types of network transmitters are drawn: nationwide and local. Nationwide programs 1502 and 2504 are transmitted by all transmitters labeled Tx in nationwide coverage areas 1502 and 2504, respectively, and received in areas within the outermost coverage areas. Localized programs A, B and C are transmitted in localized coverage areas A506, B508, and C510, respectively, and received in an area within the outermost coverage area. In each of the local areas 506-510, the transmitters transmit the same local program. However, in the area between these two different types of coverage areas, e.g. between two transmitters belonging to different national networks or different local networks, the transmitted signals may interfere, possibly resulting in "holes/gaps" in the corresponding coverage areas.

For some OFDM systems, both national and localized programs are transmitted in a Time Division Multiplexed (TDM) fashion 600, as shown in fig. 6. As a result, national and local transmissions do not interfere with each other because they are transmitted in different time frames. However, nationwide or localized transmissions belonging to different networks interfere with each other, creating holes/gaps between coverage areas. For example, in a wireless communication system, the frequency is divided into 8 interlaces. The pilot signal and data are transmitted on different interlaces. For the (2, 6) pilot staggering pattern, pilot signals are transmitted alternately on interlace 2 and interlace 6 from OFDM symbol to OFDM symbol. For the (0, 3, 6, … …) mode, the pilot is transmitted in interlaces 0, 3, 6, 1, 4, 7, 2, 5 and repeated from OFDM symbol to OFDM symbol. The data can utilize all of the remaining interlaces. Fig. 7 illustrates a structure 700 that utilizes the same frequency interleaving at the beginning of a frame with two exemplary pilot staggering patterns.

In this structure 700, all networks transmit pilot and data in the same interlace at any OFDM symbol time. Thus, the probability of collision between pilot signals from different networks is 100%. Note that the pilot signal is always present. However, this is not the case for data, i.e. because the scheduler is not ideal or the data load is small, not all the interlaces put aside for data are used by data, resulting in unoccupied interlaces occurring from time to time. These unoccupied interlaces transmitted by the network create "breathing space" for data interlaces of other networks. However, the pilot always experiences full interference regardless of the system data load. For example, for the (2, 6) spread shown in fig. 7, at time 1 of frame n, the pilot interlaces for network 1 and network 2 are both 6, and therefore the pilots for both networks interfere with each other. However, some of the interlaces used by network 1 frame n at time 1 may not be used by network 2, depending on the scheduling and system load, and therefore will not receive any interference from network 2. This imbalance between pilot and data makes this architecture ultimately "pilot interference limited," i.e., reducing system load (reducing overall interference between networks) does not improve reception quality or coverage.

A randomized pilot frequency interleaving structure 800 in one embodiment of the invention is illustrated in fig. 8. The present invention can reduce the imbalance between pilot signals and data. Fig. 8 depicts a pilot structure 800 that uses random pilot interleaving at the beginning of a frame. As an example, two guided stagger modes are drawn. At the beginning of each frame, the starting interlace of the pilot stagger sequence is determined randomly, i.e., the pilot interlace number is determined by a random number generator, for example using a pseudo-noise (PN) sequence generator seeded by the network ID number. The pilot interleaving of the subsequent OFDM symbols is determined by the staggering sequence. For the (2, 6) stagger mode, the pilot interlace for the first OFDM symbol of the frame is randomly selected from interlace 2 and interlace 6. For the (0, 3, 6, … …) interlace pattern, the pilot interlace for the first OFDM symbol of each frame is randomly selected from 8 interlaces (interlace 0 through interlace 7). This reduces the probability of collision between the pilots of the two networks. For example, for the (2, 6) spread case in fig. 8, at time 1 of frame n, the pilot spread for network 1 is 2 and for network 2 is 6. Interlace 2 of network 1 may not be occupied by data for this OFDM symbol and thus, the pilot signal for network 1 may not receive interference from network 2 for this OFDM symbol. Therefore, the pilot signal can utilize a non-interference gap like data. This effectively improves the balance between pilot and data and thus improves reception quality and/or coverage. It also makes the system more scalable, i.e., the system bandwidth can be made coverage tradeoff. That is, the system load can be reduced to improve coverage.

In view of the exemplary systems shown and described above, methodologies that may be implemented in accordance with the present invention may be better appreciated with reference to the flow charts of FIGS. 9-10. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of blocks, it is to be understood and appreciated that the present invention is not limited by the order of the blocks, as some blocks may, in accordance with the present invention, occur in different orders and/or concurrently with other blocks. Moreover, not all illustrated blocks may be required to implement the methodologies of the present invention.

In fig. 9, a flow chart of a method 900 of supporting data communication in one embodiment of the invention is shown. The method 900 begins 902 with obtaining a pilot stagger sequence 904. A pilot interlace start number is then determined based on the interlaces of the pilot stagger sequence 906. This determination may be based on a random selection process and/or a predetermined selection process. The random selection process may also use communication system parameters or the like as seeds to further reduce the probability of generating similar pilot staggering sequences for the two networks. The predetermined selection process may also employ communication system parameters. This allows for automatic determination so that, for example, the networks in a particular system have a maximum probability of not interfering with each other. The selection system can be constructed by maximizing a probability equation based on the available interlaces from the pilot staggering sequence and a predetermined method of offsetting the starting interlace of each network. The offset itself may be predetermined and/or biased according to communication system parameters. The pilot staggering sequence 908 is then reinitialized with the pilot interlace start number, ending the process 910. In this way, additional sequences with a very high probability of interference free are generated for the network and/or a group of networks. If there is communication between the networks in the system, a higher probability of interference free can be established by ensuring that each network has a different starting interlace.

Referring to fig. 10, there is shown another flow chart of a method 1000 of supporting data communications in one embodiment of the invention. The method 1000 begins at 1002 by obtaining pilot frequency interlace information 1004. The pilot frequency interleaving information may include a sequence of interleaves that constitute a pilot stagger sequence. The network ID associated with the pilot frequency interlace information is then also obtained 1006. Other communication system and/or network parameters may also be used with the present invention. A random generator, such as a PN sequence generator seeded by the network ID, is then used to generate a random initial interlace number based on the pilot interlace information 1008, ending 1010. The communication system may then use this initial or starting staggering number to reduce the probability of pilot interference by enhancing their pilot staggering sequence.

Fig. 11 is a block diagram of an example communication system environment 1100 in which the present invention can be utilized. The system 1100 also depicts two representative communication systems a1102 and B1104. One possible communication between systems a1102 and B1104 may be in the form of data packets to be transmitted between two or more communication systems. The system 1100 includes a communication framework 1106 that can be employed to support communications between communication system a1102 and communication system B1104.

In one embodiment, a data packet transmitted between two or more communication system components supporting data communication includes, at least in part, information related to an initial pilot staggering sequence interlace selected for reducing pilot signal collision.

What has been described above includes examples of the subject invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims. Further, "comprising" means similar to "comprising".

Claims (44)

1. A method of supporting data communications, comprising:

obtaining a pilot spread sequence of the pilot signal; and

shifting an order of the pilot staggering sequence to reduce collision of the pilot signal with other pilot signals.

2. The method of claim 1, further comprising:

the shifted order of the pilot staggering sequence is used in the first symbol of a frame of communication signals.

3. The method of claim 1, translating an order of the pilot staggering sequence comprising:

determining a pilot interlace start number based on the interlaces of the pilot stagger sequences; and

using the pilot interlace start number as an initial interlace of the pilot stagger sequence.

4. The method of claim 3, further comprising:

utilizing at least one communication system parameter to support determining the pilot interlace start number.

5. The method of claim 4, the communication system parameter comprising at least one network Identification (ID).

6. The method of claim 3, determining the pilot interlace start number comprises:

the pilot stagger start number is selected from the interlaces of the pilot stagger sequence using a random number generator.

7. The method of claim 6, the random number generator comprising a pseudo-noise (PN) sequence generator.

8. The method of claim 7, further comprising:

seeding the Pseudo Noise (PN) sequence generator with at least one network Identification (ID).

9. The method of claim 3, determining the pilot interlace start number comprises:

a predetermined starting interlace offset based on communication system parameters is utilized.

10. The method of claim 9, the communication system parameter comprising a network Identification (ID).

11. A multimedia communication system employing the method of claim 1.

12. A system for supporting data communications, comprising:

a receiving component that receives at least one pilot staggering sequence for at least one pilot signal; and

a sequence determination component that shifts an order of the pilot staggering sequence to reduce a probability that the pilot signal collides with other pilot signals.

13. The system of claim 12, the sequence determination component supports ordering the shifted pilot stagger sequence using a start stagger number derived from the staggering of the pilot stagger sequence.

14. The system of claim 13, the sequence determination component utilizes at least one communication system parameter to support determining the starting staggering number.

15. The system of claim 14, the communication system parameter comprising a network Identification (ID).

16. The system of claim 13, the sequence determination component utilizes a random number generator to support deriving the starting cross number.

17. The system of claim 16, the random number generator comprising a pseudo-noise (PN) sequence generator.

18. The system of claim 17, the sequence determination component utilizes at least one network Identification (ID) to seed the pseudo-noise (PN) sequence generator.

19. The system of claim 13, the sequence determination component supports determining the start interlace number using a predetermined start interlace offset based on communication system parameters.

20. The system of claim 19, the communication system parameter comprising a network Identification (ID).

21. A multimedia communication system employing the system of claim 12.

22. An OFDM-based communication system that employs the system of claim 12 to remove pilot carrier signal interference limitations.

23. A system for supporting data communications, comprising:

means for receiving at least one pilot staggering sequence for at least one pilot signal; and

means for shifting an order of the pilot staggering sequence to reduce collision of the pilot signal with other pilot signals.

24. The system of claim 23, further comprising:

means for supporting shifting an order of the pilot staggering sequences using communication system parameters.

25. The system of claim 23, further comprising

Means for randomly selecting a starting position of the order in which the pilot staggering sequence is shifted.

26. The system of claim 23, further comprising:

means for supporting ordering of the shifted pilot staggering sequence with a start stagger number derived from the staggering of the pilot staggering sequence.

27. The system of claim 26, further comprising:

means for utilizing at least one communication system parameter to support determining the starting staggering number.

28. The system of claim 27, the communication system parameter comprises a network Identification (ID).

29. The system of claim 26, further comprising:

means for utilizing a random number generator to support deriving the start error number.

30. The system of claim 29, the random number generator comprising a pseudo-noise (PN) sequence generator.

31. The system of claim 30, further comprising:

means for seeding the pseudo-noise (PN) sequence generator with at least one network Identification (ID).

32. The system of claim 26, further comprising:

means for supporting determining the start interlace number with a predetermined start interlace offset based on communication system parameters.

33. The system of claim 32, the communication system parameter comprises a network Identification (ID).

34. A data packet transmitted between two or more communicating components, the data packet supporting data communications, the data packet including, at least in part, information relating to an initial pilot staggering sequence interlace selected to reduce pilot signal collision.

35. A computer-readable medium having stored therein the computer-executable components of the system of claim 12.

36. A microprocessor that executes instructions for implementing a method for supporting data communications, the method comprising:

obtaining a pilot spread sequence of the pilot signal; and

shifting an order of the pilot staggering sequence to reduce collision of the pilot signal with other pilot signals.

37. The method of claim 36, further comprising:

the shifted order of the pilot staggering sequence is used in the first symbol of a frame of communication signals.

38. The method of claim 36, translating the order of the pilot staggering sequence comprises:

determining a pilot interlace start number based on the interlaces of the pilot stagger sequences; and

using the pilot interlace start number as an initial interlace of the pilot stagger sequence.

39. The method of claim 38, further comprising:

utilizing at least one communication system parameter to support determining the pilot interlace start number.

40. The method of claim 39, the communication system parameter comprising at least one network Identification (ID).

41. The method of claim 38, determining the pilot interlace start number comprises:

the pilot stagger start number is selected from the interlaces of the pilot stagger sequence using a random number generator.

42. The method of claim 41, the random number generator comprising a pseudo-noise (PN) sequence generator.

43. The method of claim 42, further comprising:

seeding the Pseudo Noise (PN) sequence generator with at least one network Identification (ID).

44. The method of claim 38, determining the pilot interlace start number comprises:

a predetermined starting interlace offset is used based on communication system parameters.