RU2427970C2 - Searching for cells by means of beacon radio signals in wireless communication system - Google Patents

Abstract

FIELD: information technologies.

SUBSTANCE: basic station may also generate and transfer one or more beacon radio signals, which may be used by means of UE to search for neighbouring cells, in order to detect neighbouring cells. Number of beacon radio signals for transfer and a set of subcarriers suitable for use for each beacon radio signal, may be determined on the basis of system passband. Each beacon radio signal may be converted into one subcarrier from a set of subcarriers in each period of beacon radio signal symbol. This subcarrier may be determined on the basis of template of frequency hopping of beacon radio signal or code of beacon radio signal and may depend on a cell identifier (ID).

EFFECT: increased efficiency of synchronisation signals transfer, for this purpose the basic station for cell generates and transfers the main signal of synchronisation and an additional signal of synchronisation, which may be used by UE for initial cell searching when energised.

54 cl, 26 dwg

Description

This application claims the priority of provisional application for the grant of US patent No. 60/845268, entitled "A METHOD AND APPARATUS FOR USING SCALABLE BEACON SIGNALING BASED ON SYSTEM BANDWIDTH", filed September 14, 2006; provisional application for US patent No. 60/828051, entitled "A METHOD AND APPARATUS FOR P-SCH FOR E-UTRA", filed October 3, 2006; and U.S. Patent Application No. 11/853704, entitled "BEACON ASSISTED CELL SEARCH IN A WIRELESS COMMUNICATION SYSTEM", filed September 11, 2007, each of which is assigned to the assignee of this application and is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates generally to communications, and more specifically to techniques for searching for cells in a wireless communication system.

State of the art

Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple access systems capable of supporting multiple users through the sharing of available system resources. Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal FDMA systems (OFDMA), and systems Single Carrier FDMA (SC-FDMA).

A wireless communication system may include any number of base stations that can communicate for any number of user devices (UEs). A UE (e.g., a cell phone) may be within zero coverage of one or more base stations at any given moment. The UE may have just turned on or may have lost coverage and thus may not know which base stations might be received. The UE may perform a cell search to detect base stations and obtain synchronization and other information for the detected base stations. The UE may also communicate with one or more base stations and may be a mobile device. The UE may perform a cell search to detect more optimal base stations in order to serve the UE.

Each base station may transmit synchronization signals to help the UE perform cell search. In general, the synchronization signal may be any signal that enables the receiving device to detect the transmitting device and obtain information, for example, synchronization and identification data of the transmitting device. Synchronization signals represent overhead information and should be transmitted as efficiently as possible. In addition, synchronization signals should allow the UE to search for cells as quickly and efficiently as possible.

Disclosure of invention

This document describes synchronization signaling techniques to help the UE perform cell search. In one design, a base station for a cell may generate and transmit a primary synchronization signal and an additional synchronization signal, which can be used by the UE to initially search for a cell upon power up. The base station can also generate and transmit one or more beacon signals that can be used by the UE to search for neighboring cells to detect neighboring cells while the UE is in an idle and active state. A beacon signal is a signal in which all or a significant portion of the total transmit power of a cell is used for one or more subcarriers. The number of beacons for transmission and a set of subcarriers suitable for use for each beacon may be determined based on the system bandwidth. In one design, each beacon signal may be converted into one subcarrier (referred to as a subcarrier of the beacon signal) in a set of subcarriers for each symbol period in which the beacon signal is transmitted. The beacon radio subcarrier may be determined based on the beacon frequency hopping pattern or the beacon code and may depend on the cell identifier (ID) and / or other information sent in the beacon radio signal. The beacon radio signal (s) may be sent using time division multiplexing (TDM) or frequency division multiplexing (FDM).

In one design, the UE may perform an initial cell search based on the primary and secondary synchronization signals transmitted by the cells in the system. The UE may determine the system bandwidth, for example, based on system information received from the detected cell. The UE may determine a set of subcarriers suitable for use for beacon signals based on the system bandwidth. When operating in an idle or active state, the UE may periodically search for neighboring cells to detect beacon radio signals from neighboring cells, based on a set of subcarriers.

Various aspects and features of the invention are described in more detail below.

Brief Description of the Drawings

Figure 1 illustrates a wireless communication system.

FIG. 2 illustrates synchronization signaling for a TDM scheme.

3A-3C illustrate TDM beacon transmission for various system bandwidths.

Figure 4 illustrates the transmission of synchronization signals for the FDM scheme.

5A-5C illustrate FDM beacon transmission for various system bandwidths.

6 illustrates a beacon radio signal for one cell.

7 illustrates beacon radio signals for three cells.

8 illustrates a block diagram of a node B and a UE.

FIG. 9 illustrates a block diagram of a beacon signal generator at node B.

10 illustrates a block diagram of a beacon radio processor in a UE.

11 illustrates the process of transmitting beacon radio signals through node B.

12 illustrates a device for transmitting beacon radio signals.

13 illustrates a process for detecting beacon signals by a UE.

14 illustrates an apparatus for detecting beacon radio signals.

Fig. 15 illustrates a process for transmitting synchronization signals by a node B.

16 illustrates an apparatus for transmitting synchronization signals.

17 illustrates a process for performing cell search by a UE.

Fig. 18 illustrates an apparatus for performing cell search.

FIG. 19 illustrates a process for transmitting FDM beacon signals through a Node B.

FIG. 20 illustrates an apparatus for transmitting FDM beacon signals.

21 illustrates a process for receiving FDM beacon signals by a UE.

22 illustrates an apparatus for receiving FDM beacon signals.

The implementation of the invention

The techniques described herein can be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system can implement such radio technology as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes wideband CDMA (W-CDMA) and low chip rate (LCR). CDMA2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system can implement such radio technology as Enhanced UTRA (E-UTRA), Ultra Broadband Mobile Transmission (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. .d. UTRA, E-UTRA and GSM are part of the Universal Mobile Communications System (UMTS). Long Term Evolution (LTE) 3GPP is an upcoming version of UMTS that uses E-UTRA, which uses OFDMA in the downlink and SC-FDMA in the uplink. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents from an organization called the Third Generation Partnership Project (3GPP). CDMA2000 and UMB are described in documents from an organization called the Third Generation Partnership Project 2 (3GPP2). These various radio technologies and standards are known in the art. For clarity, certain aspects of the techniques are described below for LTE, and LTE terminology is used in much of the description below.

LTE uses orthogonal frequency division multiplexing (OFDM) in the downlink and frequency division multiplexing on one carrier (SC-FDM) in the uplink. OFDM and SC-FDM partition the system bandwidth into several (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system bandwidth. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. To form an OFDM symbol, non-zero value symbols can be converted to subcarriers used for transmission, and zero-value symbols can be converted to remaining subcarriers. K characters can be converted to a time domain to obtain K time-domain samples. The last C samples can be copied and added to the beginning of K samples to get an OFDM symbol containing K + C samples. The copied samples are referred to as a cyclic prefix, and C is the length of the cyclic prefix.

1 illustrates a wireless communication system 100 with multiple Nodes B 110. Node B is, in general, a fixed station that communicates with the UE, and may also be referred to as Enhanced Node B (eNB), base station, access point, and etc. Each node B 110 provides communication coverage for a specific geographic area. The total coverage area of each node B 110 can be partitioned into several (for example, three) smaller areas. In 3GPP, the term "cell" may be referred to as the smallest coverage area of node B and / or the subsystem of node B serving this coverage area. In other systems, the term “sector” may be referred to as the smallest coverage area and / or subsystem serving this coverage area. For clarity, the concept of a cell from 3GPP is used in the description below.

UE 120 may be distributed throughout the system. The UE may be fixed or mobile, and may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, etc. The UE may be a cell phone, a personal digital device (PDA), a wireless modem, a wireless device, a handheld device, a trip computer, a cordless phone, etc. The UE may communicate with one or more nodes B via transmissions in the downlink and uplink. The downlink (or forward link) refers to the communication link from nodes B to UE, and the uplink (or reverse link) refers to the communication link from UE to nodes B. In FIG. 1, a solid line with double arrows indicates communication between node B and UE. The dashed line with one arrow indicates the reception by the UE of the downlink signal from the node B. The UE may search for cells based on the downlink signals transmitted by the nodes B.

In system 100, nodes B 110 may periodically transmit synchronization signals to enable UE 120 to detect nodes B and obtain information such as synchronization, frequency offset, cell identifier, etc. Table 1 lists three types of synchronization signals that can be transmitted through node B, and provides a brief description for each type of synchronization signal.

Table 1 Symbol Sync signal Description Psc Main sync signal The synchronization signal is used to detect cells during the initial cell search. SSC Additional sync signal The synchronization signal is used to identify the cell during the initial cell search. Bsc Beacon The synchronization signal used to search for neighboring cells to detect neighboring cells

The main synchronization signal can be generated based on the sequence of the main synchronization code (PSC), sent on the main synchronization channel (P-SCH) and called the PSC signal. The PSC sequence can be a CAZAC sequence (constant-amplitude zero autocorrelation), a pseudo-random number (PN) sequence, etc. Some exemplary CAZAC sequences include a Chu sequence, a Zadoff-Chu sequence, a Frank sequence, a generalized linear frequency-modulated sequence (GCL), etc. An additional synchronization signal may be generated based on a sequence of an additional synchronization code (SSC), sent over an additional synchronization channel (S-SCH), and referred to as an SSC signal. The SSC sequence may be a maximum length sequence (M sequence), a PN sequence, a binary sequence, etc. A beacon signal may be generated based on a beacon signal code or a beacon frequency hopping pattern and sent via a beacon signal synchronization channel (B-SCH). The primary synchronization signal, the secondary synchronization signal and the beacon signal may also be referred to simply as PSC, SSC and BSC respectively. A beacon signal may also be referred to as a beacon clock signal, a beacon signal, a BSC signal, etc.

PSC and SSC for E-UTRA can be formed as described in 3GPP TS 36.211, entitled "Physical Channels and Modulation", June 2007. PSC and SSC for UTRA can be configured as described in 3GPP TS 25.213 entitled "Spreading and modulation", May 2007. 3GPP documents are publicly available. PSC and SSC can also be formed in other ways, for example, as described in the aforementioned provisional application for US patent serial number 60/828051. The BSC may be generated and transmitted as described below.

BSC can be transmitted using TDM or FDM. For a TDM scheme, the BSC may occupy the entire system bandwidth in each symbol period in which the BSC is transmitted. For an FDM scheme, the BSC may occupy part of the system bandwidth in each symbol period in which the BSC is transmitted.

Figure 2 illustrates an example transmission of these three synchronization signals in table 1 in accordance with the TDM scheme. The transmission timeline for the downlink can be partitioned in units of radio frames. Each radio frame may be further partitioned into several (S) subframes, and each subframe may include several (T) symbol periods. In one design, each radio frame is 10 milliseconds (ms) long and is partitioned into S = 10 subframes, each subframe is 1 ms long and is partitioned into two time slots, and each time slice spans 6 or 7 symbol periods depending on the length of the cyclic prefix. Radio frames can also be partitioned in other ways.

In one design, the PSC is transmitted in the last character of the first time slot in each of subframes 0 and 5, which are located at the beginning and middle of the radio frame. The SSC is transmitted immediately before the PSC in subframe 0, and the BSC is transmitted immediately before the PSC in subframe 5. In general, PSC, SSC and BSC can be transmitted at any speed (for example, any number of times in each radio frame) and can be transmitted at the same or different speeds. The SSC can be sent close to the PSC so that the channel estimate can be extracted based on the PSC and used for coherent SSC detection. The BSC can be sent at any known location in the radio frame.

In one design, all cells in a system can transmit the same PSC sequence to enable the UE to detect the presence of these cells. Different cells may transmit different SSC sequences to enable the UE to identify these cells. Different cells can also transmit BSCs using different beacon frequency hopping patterns to enable the UE to identify these cells.

A UE may operate in one of several states, such as a disconnected LTE state, an LTE inactive state, and an active LTE state. In the disconnected LTE state, the UE does not access the system and is not known to the system. The UE may turn on power in the disconnected LTE state, and thereafter may transition to the LTE inactive state or the active LTE state after accessing the system and completing registration. In the idle state of LTE, the UE may be registered with the system, but may be inactive and not have data to communicate on the downlink or uplink. In the idle state of LTE, the UE and the system may have applicable contextual information to enable the UE to quickly transition to the active LTE state. The UE may transition to an active LTE state when there is data in order to send or receive. In the LTE active state, the UE can actively communicate with the system on the downlink and / or uplink.

The UE may perform an initial cell search, for example, in the disconnected LTE state at power up, using a three-step process. In one design, a three-step process may include the following:

1. PSC detection step

a. Cell detection based on PSC transmitted by cells,

b. Obtaining symbol synchronization for each detected cell, and

c. Estimation of the frequency shift and channel response for each detected cell;

2. SSC detection step

a. Obtaining frame synchronization for each detected cell, and

b. Identification of each detected cell based on the SSC transmitted by the cell; and

3. Stage demodulation on the broadcast channel (BCH)

a. Obtaining system bandwidth, cyclic prefix length, and other system information from the BCH of the detected cell.

For the PSC detection step, symbol and frame synchronization may not be known, so that the UE can correlate the received signal with a locally generated PSC sequence for various synchronization hypotheses (or time offsets) to detect PSC sequences transmitted by cells. For the SSC detection stage, symbol synchronization may be known from the PSC detection stage, but there may be many SSC hypotheses (e.g., cell identifiers) for testing. The UE may correlate the received signal with various possible SSC sequences to detect the SSC sequence transmitted by each cell detected in the PSC detection step.

After an initial cell search, one cell may be selected in order to serve the UE. The UE may communicate with this serving cell in the LTE active state, or may wait for a call in this cell in the LTE idle state.

The UE may search for neighboring cells, for example, being in an idle state of LTE or an active state of LTE, to find better cells than the current serving cell. To search for neighboring cells, the UE may already have certain information such as system bandwidth, symbol and frame synchronization, and cyclic prefix length. In one design, the UE may search for neighboring cells by correlating the received signal with various possible SSC sequences in the same manner as for the initial cell search. However, a continuous search for neighboring cells based on correlation may consume excessive battery power in the UE. An initial cell search can only be performed once when the power is turned on, and high battery power consumption for a short period of time may be acceptable. The UE may continuously search for neighboring cells while it is on. Therefore, low search complexity may be very desirable for searching neighboring cells in order to reduce battery consumption.

In one aspect, the search for neighboring cells can be performed based on beacon radio signals transmitted by the cells. A beacon signal includes components of a narrowband signal with a high power level (for example, on one or more subcarriers), which can have much greater power than other signals, such as user data signals. The beacon signal may be composed of a sequence of beacon symbols. In one design, a beacon symbol for one beacon is an OFDM symbol in which all or most of the total transmit power of a cell is used for one subcarrier. In other designs, the beacon symbol may have all or most of the total transmit power of the cell on a small number of subcarriers. For clarity, the following description is given for a scheme in which a beacon signal uses one subcarrier in each symbol period in which the beacon signal is transmitted. Since a large amount of energy is transmitted on only one subcarrier, a beacon signal can be reliably detected even with a low signal to noise ratio (SNR).

In one design, the search for neighboring cells may include the following:

1. Beacon Detection

a. Detection of possible subcarriers with high received signal quality, and

b. Neighbor cell identification based on possible subcarriers.

After detecting the neighboring cell, the UE can measure the quality of the downlink channel for the neighboring cell based on the control channel transmitted by the cell. The UE may report the quality of the downlink channel for all detected neighboring cells to a system that can make UE handover decisions based on this report.

The system may have a configurable system bandwidth, which may be selected from a set of possible system bandwidths. In one design, possible system bandwidths include 1.25, 2.5, 5, 7.5, 10, 15, and 20 MHz. Other possible system bandwidths may also be supported. A UE may also have various characteristics that can be characterized by the bandwidths supported by these UEs. One design assumes that the UE supports a minimum bandwidth of 10 MHz.

In one design, the number of beacon signals to transmit via a cell may be configurable and determined based on system bandwidth and UE bandwidth characteristics. In general, a cell can transmit a sufficient number of beacon signals within the system bandwidth so that a UE with a minimum bandwidth characteristic can receive at least one beacon radio signal from the cell.

3A illustrates a TDM beacon transmission scheme for a system bandwidth of 20 MHz. In this scheme, the system bandwidth can be partitioned into the left half at 10 MHz and the right half at 10 MHz. One lighthouse radio signal can be transmitted in the left half, another lighthouse radio signal can be transmitted in the right half, and each lighthouse radio signal can span 10 MHz. PSC and SSC can be transmitted in the central 1.25 MHz system bandwidth. A UE with 10 MHz support can operate in either of the left or right half of the system bandwidth, and in this case has the ability to receive one of these two beacon radio signals.

Fig. 3B illustrates a TDM beacon transmission scheme for a system bandwidth of 15 MHz. In this scheme, the system bandwidth can be partitioned into the left half of 7.5 MHz and the right half of 7.5 MHz. One beacon radio signal can be transmitted in each half, and each beacon radio signal can cover 7.5 MHz. PSC and SSC can be transmitted in the center of the system bandwidth. A 10 MHz UE can operate in the left or right half of the system bandwidth.

When several beacon radio signals are transmitted, for example, as shown in FIGS. 3A and 3B, the same or different beacon radio signals can be transmitted on different parts of the system bandwidth. However, transmitting the same beacon radio signal can simplify the operation.

Fig. 3C illustrates a TDM beacon transmission scheme for a system bandwidth of 10 MHz. In this design, one beacon signal can be transmitted over the entire system bandwidth and can span 10 MHz. PSC and SSC can be transmitted in the center of the system bandwidth. A 10 MHz UE can operate across the entire system bandwidth.

The transmission of TDM beacon radio signals for the system bandwidths of 7.5, 5, 2.5 and 1.25 MHz may be similar to the transmission of TDM beacon radio signals for a system bandwidth of 10 MHz. For each system bandwidth that is equal to or less than the UE's bandwidth capabilities, one beacon signal can be transmitted over the entire system bandwidth.

Figure 4 illustrates an example transmission of these three synchronization signals in table 1 in accordance with the FDM scheme. In one design, a radio frame includes 10 subframes, a PSC is transmitted in each of subframes 0 and 5, and an SSC is transmitted immediately before the PSC. The BSC may be transmitted with the PSC as well as with the SSC, as shown in FIG. 4. Alternatively, the BSC can be transmitted only with PSC or only with SSC. In general, PSC, SSC and BSC can each be transmitted at any speed.

5A illustrates an FDM beacon transmission scheme for a system bandwidth of 20 MHz. In this scheme, the system bandwidth can be partitioned into the left half at 10 MHz and the right half at 10 MHz. PSC and SSC can be transmitted in the central 1.25 MHz system bandwidth. One beacon signal can be transmitted in the part of the left half that is not occupied by PSC and SSC. Another beacon signal may be transmitted in the part of the right half that is not occupied by PSC and SSC.

FIG. 5B illustrates an FDM beacon transmission scheme for a system bandwidth of 15 MHz. In this scheme, the system bandwidth can be partitioned into the left half of 7.5 MHz and the right half of 7.5 MHz. PSC and SSC can be transmitted in the central 1.25 MHz system bandwidth. One beacon signal may be transmitted in each half in a part that is not occupied by PSC and SSC.

5C illustrates an FDM beacon transmission scheme for a system bandwidth of 10 MHz. PSC and SSC can be transmitted in the central 1.25 MHz system bandwidth. One beacon may be transmitted in the remainder of the system bandwidth that is not occupied by PSC and SSC. FDM beacon transmission for system bandwidths of 7.5, 5 and 2.5 MHz may be similar to FDM beacon transmission for a system bandwidth of 10 MHz.

As shown in FIGS. 4-5C, the BSC can be frequency division multiplexed by PSC and SSC in one OFDM symbol when the system bandwidth is more than 1.25 MHz. BSC overhead can be eliminated by using FDM.

In one FDM beacon scheme, the total transmit power of a cell can be divided evenly across all K subcarriers. The amount of transmit power to use for each subcarrier of the beacon signal can then be determined based on the number of suitable subcarriers to use. For a system bandwidth of 20 MHz, 1/8 of the total transmit power of the cell can be used for PSC or SSC, 7/16 of the full transmit power of the cell can be used for the beacon subcarrier to the left of the PSC / SSC, and the remaining 7/16 -x full transmit power, cells can be used for the beacon subcarrier to the right of the PSC / SSC. For a system bandwidth of 10 MHz, 1/4 of the total transmit power of the cell can be used for PSC or SSC, and the remaining 3/4 of the total transmit power of the cell can be used for the beacon subcarrier to the right or left of the PSC / SSC. The total transmit power of the cell can also be allocated to the beacon radio signal (s) and PSC / SSC in other ways.

In the circuits shown in FIGS. 3A-3C and FIGS. 5A-5C, the PSC and SSC are sent at 1.25 MHz and are located at the center of the system bandwidth. This enables the UE to perform an initial cell search based on PSC and SSC regardless of system bandwidth. PSC and SSC can also be transmitted in other ways, for example, sent on a different bandwidth and / or placed in other locations within the system bandwidth.

After completing the initial cell search and performing other procedures, the UE may be instructed to operate along all or part of the system bandwidth. Cells can transmit beacon signals so that the UE can detect these cells without having to switch the frequency. For example, for a system bandwidth of 15 or 20 MHz, a 10 MHz UE operating on both sides of the system bandwidth should be able to receive beacon radio signals from neighboring cells without frequency switching.

In one design, the spacing between adjacent subcarriers is fixed at 15 kHz, and the total number of subcarriers depends on the system bandwidth. Table 2 lists the set of possible system bandwidths and the total number of subcarriers (K) for each system bandwidth in accordance with one design.

table 2 System Bandwidth (MHz) FFT size N The total number of subcarriers K The number of suitable subcarriers M Beacon Bandwidth (MHz) 1.25 128 75 24 1,08 2.5 256 150 48 2.16 5 512 300 92 4.32 7.5 768 450 144 6.48 10 1024 600 184 8.64 fifteen 1536 900 144 6.48 twenty 2048 1200 184 8.64

A suitable subcarrier is a subcarrier that can be used to send a beacon signal. A set of M suitable subcarriers for use may be defined based on all K subcarriers, where, in general, M <K. In one design, all K subcarriers may be used to send one or more beacon radio signals. In other designs, a subset of K subcarriers may be used to send one or more beacon signals.

In one design, the number of usable subcarriers for a beacon signal is scalable and varies as a function of system bandwidth. For the TDM beacon scheme shown in Table 2, every third subcarrier may be used to send the beacon, and suitable subcarriers are spaced 45 kHz apart. For a system bandwidth of 10 MHz or less, one beacon may be sent, and the number of usable subcarriers may be approximately one third of the total number of subcarriers, or M ~ K / 3. For a system bandwidth of more than 10 MHz, two beacon signals may be sent, and the number of usable subcarriers for each beacon may be approximately one sixth of the total number of subcarriers, or M ~ K / 6. A larger number of usable subcarriers for large system bandwidths can be used to support more cell identifiers, reduce the length of the beacon frequency hopping pattern, reduce the search time for neighboring cells, etc.

In another design, every second subcarrier may be used to send a beacon signal, and suitable subcarriers are spaced 30 kHz apart. A multiple of 32 subcarriers may be suitable for use with a beacon signal, depending on the system bandwidth.

In yet another design, the number of usable subcarriers for a beacon signal may be fixed, and the spacing between usable subcarriers may vary as a function of system bandwidth. For example, the spacing of usable subcarriers may be 45 kHz for a system bandwidth of 1.25 MHz, 90 kHz for a system bandwidth of 2.5 MHz, etc.

In general, any number of usable subcarriers may be specified, and usable subcarriers may be spaced by any amount. The number of usable subcarriers and the spacing of usable subcarriers can be selected based on the total number of subcarriers, the required minimum number of usable subcarriers, the required minimum diversity between usable subcarriers, etc. The same number of usable subcarriers and the same diversity can be used for all beacon symbols. Alternatively, the number of usable subcarriers and / or diversity may vary for different beacon symbols.

6 illustrates a beacon radio signal for one cell in accordance with the FDM scheme. In this design, the beacon signal is composed of one beacon symbol in each radio frame. In one design, a beacon symbol may be sent in a symbol period reserved for transmitting beacon signals, for example, as shown in FIG. In another design, a beacon symbol may replace (or thin out) another OFDM symbol. In any case, beacon symbols may be transmitted at locations that are known a priori by the UE.

A beacon radio subcarrier is a subcarrier, all or most of the transmit power of which is used for the beacon radio signal. The beacon subcarrier may be selected from a set of suitable subcarriers. As shown in FIG. 6, different beacon radio subcarriers may be used for different beacon symbols, and the beacon radio subcarrier may vary from one beacon symbol to the next. In the example shown in FIG. 6, the subcarrier X _{t-1 is} used for the beacon symbol transmitted in the radio frame t-1 , the subcarrier X _{t is} used for the symbol of the beacon radio signal transmitted in the radio frame t , the subcarrier X _{t + 1 is} used for the beacon symbol the radio signal transmitted in the t + 1 radio frame, etc.

Since all or most of the total transmit power of the cell can be used for one subcarrier in the symbol of the beacon signal, a very high SNR can be achieved for the subcarrier of the beacon signal. For example, the SNR of a beacon radio subcarrier can be increased by 10 log ₁₀ (75) = 18.75 dB, if one of the 75 subcarriers is used for a radio beacon subcarrier with a system bandwidth of 1.25 MHz, increased by 10 log ₁₀ (300) = 24.77 dB if one of the 300 subcarriers is used for the sub-carrier of a beacon radio signal with a system bandwidth of 5 MHz, etc. In addition, the amount of overhead information for a beacon signal may be relatively small. For example, if a beacon symbol is transmitted in one symbol period in each radio frame of 140 symbol periods (for example, with 10 subframes / radio frames and 14 symbol periods / subframes), then the beacon radio overhead is only 0.7%.

7 illustrates exemplary beacon transmissions for three cells A, B, and C in accordance with an FDM scheme. In this scheme, each cell can transmit one beacon symbol in one symbol period in each radio frame, and all three cells can transmit its beacon symbols in the same symbol period. However, these three cells can transmit their beacon symbols on different beacon subcarriers, which can be determined based on beacon frequency hopping patterns or beacon codes for these cells. In another design, different cells may transmit their beacon symbols in different symbol periods to avoid conflicts of their beacon subcarriers.

In general, any type of information and any amount of information can be sent in a beacon radio signal. The number of information bits (L) that can be sent in the beacon signal can be determined by the number of suitable subcarriers (M) for the beacon signal and the number of beacon symbols (Q) in which the information is sent. As an example, if a beacon signal is sent in 24 suitable subcarriers, then one of 24 ² = 576 possible values (or a 9-bit value) can be sent in two characters of the beacon signal. As another example, if a beacon signal is sent in 32 suitable subcarriers, then one of 32 ² = 1024 possible values (or a 10-bit value) can be sent in two characters of the beacon signal. Alternatively, a 9-bit value may be sent with 32 suitable subcarriers (e.g., spaced at 30 kHz) for one beacon symbol and with 16 suitable subcarriers (e.g., spaced at 60 kHz) for another beacon symbol . In general, up to [log ₂ (M ^Q )] information bits can be sent in a beacon radio signal over M suitable for use subcarriers in the Q symbols of the beacon radio signal. Information may be sent to more than the minimum number (Q) of beacon symbols to increase reliability, increase frequency diversity, and improve false alert rate for a given detection probability.

In one design, a beacon signal carries a cell identifier. For the circuit shown in Table 2 with M = 24 for a system bandwidth of 1.25 MHz, a 9-bit cell identifier can be sent in a beacon radio signal in two beacon symbols. A beacon may also carry other information.

In one design, each cell is assigned a cell-specific beacon frequency hopping pattern, which indicates which subcarrier to use for the beacon subcarrier in each symbol of the beacon signal. For example, 512 different beacon frequency hopping patterns can be defined and associated with 512 possible cell identifiers, one beacon radio hopping pattern for each cell identifier. Different sets of 512 beacon frequency hopping patterns can also be specified for different system bandwidths, one set for each system bandwidth. Each cell can transmit its own beacon signal using the beacon frequency hopping pattern for its cell identifier. The beacon frequency hopping patterns may be defined such that for any two consecutive beacon symbols, the different cell identifiers are associated with unique beacon carrier subcarrier pairs. For example, 512 cell identifiers may be associated with 512 unique beacon radio subcarrier pairs in two consecutive beacon symbols. This should enable the UE to then detect all neighboring cells using any two beacon symbols.

Cells in the system may be assigned frequency hopping patterns of the beacon signal so that their beacon subcarriers do not conflict. For example, if there are M = 24 suitable subcarriers for use, then up to 24 different cells can transmit their beacon radio signals to 24 different subcarriers in a given symbol period. The length of the beacon frequency hopping patterns may depend on the number of subcarriers suitable for use and the number of possible cell identifiers. A larger system bandwidth can provide more suitable subcarriers for use and allow the use of shorter beacon frequency hopping patterns, which reduces the search time for neighboring cells.

To detect a beacon, the UE may perform OFDM demodulation during each symbol period in which the beacon symbol is sent, and obtain K received symbols for all K subcarriers. The UE may determine the received signal quality of each subcarrier based on the received symbol for that subcarrier, compare the received signal quality of each subcarrier with a threshold value and store the possible subcarriers with the received signal quality exceeding the threshold value. The UE may also use received power and / or some other metric in order to identify possible subcarriers. The UE may store a list of possible subcarriers for various beacon symbols. The UE can then identify neighboring cells based on a list of possible subcarriers and known cell-specific beacon frequency hopping patterns for all possible cell identifiers.

In another design, each cell is assigned a cell-specific beacon code, which indicates which subcarrier to use for the beacon subcarrier in each beacon symbol. The beacon code may be a maximum diversity code (MDS) code that can generate codewords having the largest possible minimum distance between codewords, and thus provides the greatest opportunity to correct errors of a given redundancy value. The Reed-Solomon code is one example of an MDS code. Some polynomial codes may also have certain MDS code characteristics.

In one example Reed-Solomon code scheme, M subcarriers are used to transmit a beacon signal, and they are assigned indices from 0 to M-1, where M may depend on the system bandwidth. The symbols of the beacon signal are transmitted at different times specified by the index t , where 0≤ t <∞ . For a beacon symbol with an index t , the beacon may be transmitted on a subcarrier with an index X _t , which can be expressed as follows:

обозначает сложение по модулю.where p ₁ is a primitive element of the field Z _M and p ₂ = p ₁ ² , α ₁ and α ₂ are the exponential coefficients determined based on the cell identifier, Z is the upper end of the range for α ₁ , and

denotes modulo addition.

Field Z _M contains M elements from 0 to M-1. A primitive element of the field Z _M is an element of Z _M that can be used to form all M-1 nonzero elements of Z _M. As an example, for a field Z ₇ containing seven elements from 0 to 6, 5 is a primitive element of Z ₇ and can be used to form all six nonzero elements of Z ₇ as follows: 5 ⁰ modulo 7 = 1, 5 ¹ modulo 7 = 5, 5 ² modulo 7 = 4, 5 ³ modulo 7 = 6, 5 ⁴ modulo 7 = 2 and 5 ⁵ modulo 7 = 3.

In equation (1), arithmetic operations are performed on the field Z _M. For example, the summation of A and B can be specified as (A + B) modulo M, the multiplication of A by B can be specified as (A × B) modulo M, the raising degree B can be specified as A ^B modulo M and t .d. Summation within exponents is an integer summation modulo M.

Different beacon codes can be set with different Z and M. The beacon codes shown in equation (1) are periodic with a period of P = M / Z characters. Therefore, X _t = X _{t + P} for any given t .

The coefficients of the exponent α ₁ and α ₂ can be set as follows:

The cell identifier (or message) can be converted to α ₁ and α ₂ as follows:

The UE may retrieve the cell identifier sent in the beacon signal using two consecutive beacon symbols in the presence of one cell even without time information. For example, the UE may receive two beacon symbols x ₁ and x ₂ at times t and t + 1. The received beacon symbols may be expressed as follows:

The set of equations (4) can be expressed in matrix form as follows:

where p ₁ ^Z and p ₂ ^Z are equal to two specific elements of the field Z _M.

в уравнении (5) следующим образом:UE can find members

in equation (5) as follows:

следующим образом:UE can get an exponent

in the following way:

The logarithm in equation (7) is taken over the field Z _M. This y value corresponds to a specific z value. Converting from y to z can be done using the lookup table or some other method. The exponent coefficient α ₁ and the time index t can be obtained from equation (7) as follows:

α ₁ = z ₁ mod Z, and equation (8a) t = z ₁ div Z. equation (8b)

, чтобы получить

, и затем нахождения α₂ на основе

.The coefficient α ₂ can be determined by replacing t obtained from equation (8b) by

, To obtain

, and then finding α ₂ based

.

The UE may also recover the cell identifier from the beacon using any two inconsistent beacon symbols in the presence of one cell. The elements of matrix A are dependent on the beacon symbols received by the UE. The UE may also recover cell identifiers from beacon radio signals transmitted by two cells using three consecutive beacon symbols.

The beacon code shown in equation (1) can be used to generate beacon frequency hopping patterns for all possible cell identifiers. Other beacon codes may also be used for beacon signals.

FIG. 8 illustrates a block diagram of the structure of a node B 110 and a UE 120, which are one of the nodes B and one of the UEs in FIG. 1. In this structure, the node B 110 is equipped with T antennas 824a-824t, and the UE 120 is equipped with R antennas 852a-852r, where, in general, T≥1 and R≥1.

At node B 110, a transmit (TX) data processor 814 may receive traffic data for one or more UEs from a data source 812. TX data processor 814 may process (eg, format, encode, and interleave) traffic data for each UE based on one or more coding schemes selected for that UE to obtain encoded data. TX data processor 814 can then modulate (or perform symbol conversion) the encoded data for each UE based on one or more modulation schemes (eg, BPSK, QSPK, PSK or QAM) selected for that UE to obtain modulation symbols.

TX MIMO processor 820 can multiplex modulation symbols for all pilot symbols UEs using any multiplexing scheme. The pilot signal is typically known data that is processed in a known manner and can be used by the receiving device for channel estimation and other purposes. The TX MIMO processor 820 can process (e.g., pre-encode) multiplexed modulation symbols and pilot symbols and provide T output symbol streams to T transmitters (TMTR) 822a-822t. In certain TX schemes, the MIMO processor 820 may apply beamforming weights to modulation symbols to spatially correct these symbols. Each transmitter 822 may process a corresponding output symbol stream (eg, for OFDM) to obtain a noise-like sequence output symbol stream. Each transmitter 822 may further process (eg, convert to analog, amplify, filter, and upconvert) the output stream of symbols of a noise-like sequence to obtain a downlink signal. T downlink signals from transmitters 822a through 822t may be transmitted through T antennas 824a through 824t, respectively.

At UE 120, antennas 852a through 852r may receive downlink signals from Node B 110 and provide received signals to receivers (RCVRs) 854a through 854r, respectively. Each receiver 854 may result in the desired parameters (e.g., filter, amplify, down-convert and digitize) the corresponding received signal to obtain samples, and may further process the samples (e.g., for OFDM) to obtain received symbols. A MIMO detector 860 can receive and process received symbols from all R receivers 854a-854r based on a MIMO receiver processing technique to obtain detected symbols that are estimates of the modulation symbols transmitted by node B 110. Receive (RX) data processor 862 then it can process (eg, demodulate, deinterleave, and decode) the detected symbols and provide decoded data for UE 120 to data receiver 864. In general, the processing by the MIMO detector 860 and the RX data processor 862 is complementary to the processing by the TX MIMO processor 820 and TX data processor 814 in the Node B 110.

On the uplink, at UE 120, traffic data from data source 876 and service signals can be processed by TX data processor 878, further processed by modulator 880, adjusted to desired parameters by transmitters 854a-854r, and transmitted to node B 110 At Node B 110, uplink signals from UE 120 may be received via antennas 824, adjusted to desired parameters by receivers 822, demodulated by demodulator 840, and processed by RX data processor 842 to obtain traffic data and service signals transmitted by the UE 120.

Controllers / processors 830 and 870 may direct operation at node B 110 and UE 120, respectively. Storage devices 832 and 872 can store data and program codes for node B 110 and UE 120, respectively. Sync processor 874 may perform an initial cell search and search for neighboring cells based on samples from receivers 854 and may provide cell identifiers and other information for the detected cells. Scheduler 834 may dispatch UEs for downlink and / or uplink transmission and may provide resource assignments for scheduled UEs.

FIG. 9 illustrates a block diagram of a structure of a beacon signal generator 900, which includes a beacon symbol generator 910 and an OFDM modulator 930. The generator 910 may be part of the TX data processor 814 at node B 110, and the OFDM modulator 930 may be part of each transmitting device 822.

Within the beacon symbol generator 910, module 912 may receive the system bandwidth and determine a set of suitable subcarriers for the beacon radio signal based on the system bandwidth. Module 914 may receive a cell identifier and / or other information and determine a beacon frequency hopping pattern or a beacon code based on the received information. For each beacon symbol, a selector 916 may select a beacon radio subcarrier from a set of suitable subcarriers based on the beacon frequency hopping pattern or the beacon code. One or more beacon signals may be transmitted depending on the system bandwidth. For each beacon symbol, a transform module 918 may convert the high power symbol to a beacon radio subcarrier for each beacon and may convert symbols with zero values to the remaining subcarriers. A multiplexer (Mux) 920 may multiplex characters from a shaper 910 with other characters for TDM or FDM.

Within the OFDM modulator 930, an inverse discrete Fourier transform (IDFT) module 932 can perform IDFTs for K symbols from multiplexer 920 during each beacon symbol period and provide K time-domain samples. The cyclic prefix insertion unit 934 can add a cyclic prefix to K time-domain samples by copying C last samples and adding these C samples before K samples. Module 934 may provide an OFDM symbol comprising a high power symbol on each subcarrier of the beacon radio signal and zero values on the remaining subcarriers used for the beacon radio signal (s).

10 illustrates a block diagram of a structure of a beacon radio processor 1000, which includes an OFDM demodulator 1010 and a beacon radio detector 1020. OFDM demodulator 1010 may be part of each receiver 854 in UE 120, and beacon detector 1020 may be part of synchronization processor 874.

Within the OFDM demodulator frames 1010, for each received OFDM symbol, the cyclic prefix removal module 1012 can remove the cyclic prefix and provide K received samples. Discrete Fourier Transform (DFT) module 1014 may perform DFT for K received samples and provide K received symbols.

Within the beacon radio detector 1020, the module 1022 can detect possible subcarriers in each symbol of the beacon radio signal. Within module 1022, module 1024 may calculate the signal quality of each received symbol and provide the received signal quality of the corresponding subcarrier. Comparator 1026 can compare the received signal quality of each subcarrier with a threshold value and provide subcarriers with a received signal quality greater than the threshold value as possible subcarriers. Module 1028 may receive system bandwidth and determine a set of suitable subcarriers based on system bandwidth. A beacon radio pattern detector 1030 may detect cell identifiers based on possible subcarriers, a set of suitable subcarriers, and a beacon radio hopping pattern for all possible cell identifiers. Alternatively, detector 1030 may detect cell identifiers based on a beacon code.

11 illustrates a design of a process 1100 for transmitting beacon signals. Process 1100 may be performed by a transmitting device, such as a Node B, a repeater, a radio station, etc. The system bandwidth can be determined from the set of possible system bandwidths (block 1112). A set of subcarriers suitable for use for the beacon signal may be determined based on the system bandwidth (block 1114). Suitable subcarriers may have a predetermined spacing, and the number of suitable subcarriers may depend on the system bandwidth, for example, as shown in Table 2. Alternatively, the number of suitable subcarriers may be fixed, and the spacing between suitable subcarriers may depend on system bandwidth. In any case, a beacon signal may be generated based on the set of subcarriers (block 1116). A beacon may be transmitted to help the receivers detect the transmitting device / cell, for example, to help the UE search for neighboring cells in order to detect neighboring cells while the UE is idle and active (step 1118). The cell may correspond to any type of transmitter.

In one design of step 1116, the beacon signal may be converted to one subcarrier (or subcarrier of the beacon signal) in the set of subcarriers in each symbol period in which the beacon signal is transmitted. In one design, the beacon frequency hopping pattern may be determined based on the cell identifier, and the beacon radio subcarrier may be selected from a set of subcarriers based on the beacon frequency hopping pattern. In another design, the beacon subcarrier may be selected from a set of subcarriers based on the beacon code, which may indicate which subcarrier to use for the beacon in each period of the beacon symbol. In general, one or more subcarriers may be selected from a set of subcarriers in each beacon symbol period based on any scheme.

A beacon signal can be sent using TDM, and only a beacon signal can be converted to the system bandwidth in each period of the beacon symbol. The beacon signal may also be sent using FDM, and the beacon signal and at least one other signal may be converted to different parts of the system bandwidth in each period of the beacon symbol.

The number of beacon signals for transmission can be determined based on the system bandwidth. For example, one beacon radio signal may be transmitted if the system bandwidth is equal to or less than a predetermined value, and several beacon radio signals may be transmitted if the system bandwidth is greater than a predetermined value.

12 illustrates a design of an apparatus 1200 for transmitting beacon radio signals. Apparatus 1200 includes means for determining a system bandwidth from a set of possible system bandwidths (module 1212), means for determining a set of subcarriers suitable for use with a beacon radio signal based on a system bandwidth (module 1214), means for generating a beacon radio signal based on a set of subcarriers (module 1216) and means for transmitting a beacon signal to help the UE search for neighboring cells to detect neighboring cells (module 1218).

13 illustrates a design of a beacon radio signal detection process 1300. Process 1300 may be performed by a receiver, such as a UE, etc. The system bandwidth can be determined from the set of possible system bandwidths, for example, based on system information received from a cell detected during an initial cell search (block 1312). A set of subcarriers suitable for use for beacon signals may be determined based on the system bandwidth (block 1314). Beacon signals may be detected based on a set of subcarriers (block 1316). The receiving device may periodically search for neighboring cells in order to detect lighthouse radio signals from neighboring cells, while operating in an idle or active state.

In one design of block 1316, demodulation may be performed for each symbol period in which beacon signals are transmitted to obtain received symbols. Possible subcarriers with a received signal quality exceeding a threshold value can be determined based on the received symbols. Cells transmitting beacon signals can be identified based on possible subcarriers and beacon frequency hopping patterns for various possible identifiers or a beacon code indicating which subcarrier to use for the beacon in each symbol period for each identifier. The detection of the beacon signal in step 1316 may be based on the beacon radio signals received from (i) the entire system bandwidth if it is equal to or less than a predetermined value, or (ii) part of the system bandwidth if it is greater than a predetermined value.

FIG. 14 illustrates a design of an apparatus 1400 for detecting beacon signals. Apparatus 1400 includes means for determining a system bandwidth from a set of possible system bandwidths (module 1412), means for determining a set of subcarriers suitable for use with beacon radio signals based on system bandwidth (module 1414), and means for detecting beacon radio signals based on a set of subcarriers (module 1416).

FIG. 15 illustrates a design of a process 1500 for transmitting synchronization signals via a Node B. A broadband primary synchronization signal used by a UE to detect a cell during an initial cell search may be generated, for example, based on a PSC sequence (block 1512). The wideband secondary synchronization signal used by the UE to identify the cell during the initial cell search may also be generated, for example, based on the SSC sequence or pseudo-random sequence for the cell identifier (block 1514). The narrowband beacon radio signal used by the UE to search for neighboring cells may be generated, for example, based on a beacon frequency hopping pattern or a beacon code for a cell identifier (block 1516). Broadband primary and secondary synchronization signals may be sent, for example, over a fixed portion of the system bandwidth (block 1518). A narrowband beacon signal may be sent, for example, on different subcarriers at different symbol periods in which the beacon signal is transmitted (block 1520).

FIG. 16 illustrates a design of an apparatus 1600 for transmitting synchronization signals. Apparatus 1600 includes means for generating a broadband primary synchronization signal used by the UE to detect a cell during an initial cell search (module 1612), means for generating a wideband secondary synchronization signal used by a UE for identifying a cell during an initial cell search (module 1614), means for generating a narrowband beacon radio signal used by the UE to search for neighboring cells (module 1616), means for sending a wideband GOVERNMENTAL main and auxiliary synchronization signals, e.g., on the fixed part of the system bandwidth (module 1618) and means for sending the narrowband beacon signal, for example, on different subcarriers in different symbol periods in which the beacon is transmitted (module 1620).

17 illustrates a design of a process 1700 for performing cell searches by a UE. Broadband primary and / or secondary synchronization signals may be received from a fixed portion of the system bandwidth (block 1712). Narrowband beacon signals may be received from different subcarriers at different symbol periods to which the beacon signals are transmitted (block 1714). An initial cell search may be performed based on the broadband primary and secondary synchronization signals transmitted by the cells. Cells may be detected based on the broadband base synchronization signals transmitted by these cells (block 1716). The detected cells can be identified based on the wideband additional synchronization signals transmitted by these cells (block 1718). The search for neighboring cells can be performed based on narrowband beacon radio signals transmitted by cells (step 1720). Broadband additional synchronization signals can be detected based on pseudo-random sequences for a set of possible cell identifiers. Narrowband beacon signals can be detected based on a set of beacon frequency hopping patterns for a set of possible cell identifiers.

FIG. 18 illustrates a design of a cell search apparatus 1800. Device 1800 includes means for receiving broadband primary and / or secondary synchronization signals from a fixed portion of the system bandwidth (module 1812), means for receiving narrowband beacon radio signals from various subcarriers at different symbol periods to which beacon radio signals are transmitted (module 1814) , means for detecting cells based on broadband primary synchronization signals transmitted by these cells (module 1816), means for identifying detected cells on the basis of okopolosnyh additional synchronization signals transmitted by these cells (module 1818) and means for performing a search of neighboring cells based on the narrowband beacon signals transmitted by a cell (module 1820).

FIG. 19 illustrates a design of a process 1900 for transmitting FDM beacon signals via a Node B. A beacon may be generated, for example, based on a beacon frequency hopping pattern or a beacon code (step 1912). At least one other signal may also be generated (block 1914). The beacon signal and at least one other signal may be frequency division multiplexed in different parts of the system bandwidth (step 1916). The beacon signal can be converted to different subcarriers in the first part of the system bandwidth at different symbol periods in which the beacon signal is transmitted. At least one other signal may be converted to the second part of the system bandwidth during symbol periods in which a beacon signal is transmitted. At least one other signal may comprise (i) a primary synchronization signal used to detect a cell during an initial cell search, and / or (ii) an additional synchronization signal used to identify a cell during an initial cell search. The beacon radio bandwidth can be scalable and determined based on the system bandwidth. The transmit power of the beacon signal and the transmit power of at least one other signal can be determined based on the parts of the system bandwidth used for these signals.

FIG. 20 illustrates a design of an apparatus 2000 for transmitting FDM beacon signals. The device 2000 includes means for generating a beacon signal, for example, based on a frequency hopping pattern of a beacon signal or a code for a beacon signal (module 2012), means for generating at least one other signal (module 2014) and means for multiplexing with a frequency dividing the channels of the beacon radio signal and at least one other signal in different parts of the system bandwidth (module 2016).

FIG. 21 illustrates a design of a process 2100 for receiving FDM beacon signals by a UE. Beacon signals may be received from the first part of the system bandwidth (block 2112). Other signals may be received from the second part of the system bandwidth (block 2114). Beacon radio signals and other signals can be frequency division multiplexed. Other signals may comprise (i) primary synchronization signals used to detect the cell during the initial cell search, and / or (ii) additional synchronization signals used to identify the cell during the initial cell search.

FIG. 22 illustrates a diagram of an FDM beacon radio reception device 2200. The device 2200 includes means for receiving beacon radio signals from the first part of the system bandwidth (module 2212) and means for receiving other signals from the second part of the system bandwidth, while the beacon radio signals and other signals are frequency division multiplexed (module 2214).

The modules in FIGS. 12, 14, 16, 18, 20, and 22 may comprise processors, electronic devices, hardware devices, electronic components, logic circuits, memory devices, etc., or any combination of the above.

Specialists in the art should understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and symbols of a noise-like sequence, which can be given as an example throughout the description above, can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles or any combination of the above.

Specialists in the art should additionally take into account that various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure can be implemented as electronic hardware, computer software, or combinations thereof. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are described above generally in terms of their functionality. This functionality is implemented as hardware or software, depending on the specific application and structural constraints imposed on the system as a whole. Highly qualified specialists can implement the described functionality in various ways for each specific application, but such implementation decisions should not be interpreted as being a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure of the essence of this document can be implemented or performed using a general purpose processor, digital signal processor (DSP), specialized integrated circuit (ASIC), user-programmable matrix LSI (FPGA) ) or another programmable logic device, a discrete logic element or transistor logic, discrete hardware components, or any combination of the above intended for to perform the functions described in this document. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors together with a DSP core, or any other similar configuration.

The steps of a method or algorithm described in connection with the disclosure of the essence of this document can be implemented directly in hardware, in a software module executed by a processor, or in a combination of the above. A software module may reside in RAM, flash memory, ROM, EPROM type memory, EEPROM type memory, registers, a hard disk, a removable disk, a compact disk or any other form of storage medium known in the art. A typical storage medium is connected to a processor, wherein the processor can read information and write information to the storage medium. Alternatively, the storage medium may be integrated in the processor. The processor and storage medium may reside in an ASIC. ASIC can reside in a user terminal. Alternatively, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary schemes, the described functions may be implemented in hardware, software, firmware, or any combination of the above. If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and a communication medium that includes any transmission medium that facilitates moving a computer program from one place to another. Storage media can be any available media that can be accessed using a general purpose or special purpose computer. By way of example, and not limitation, these computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage device, magnetic disk storage device or other magnetic storage device, or any other medium that can be used in order to transfer or store the required means for the program code in the form of instructions or data structures, and which can be accessed by a general purpose computer or special purpose or general processor Go or special purpose. Also, any connection is correctly called a computer-readable medium. For example, if the software is transmitted from a Web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair cable, digital subscriber line (DSL), or wireless technologies such as infrared, radio transmission, and microwave media, then coaxial cable, fiber optic cable, twisted pair cable, DSL, or wireless technologies such as infrared, radio transmission, and microwave media are included in the definition of media. A disc and a disc, as used herein, include a compact disc (CD), a laser disc, an optical disc, a digital versatile disc (DVD), a floppy disk and a Blu-ray disc, and discs (disk ) typically reproduce data magnetically, while discs typically reproduce data optically with lasers. Combinations of the above should also be included in the number of computer-readable media.

The preceding description of the disclosure is provided to enable any person skilled in the art to create or use the disclosure. Various modifications to the invention should be apparent to those skilled in the art, and the general principles described herein can be applied to other variations without departing from the spirit and scope of the invention. Thus, the invention is not intended to be limited by the examples and schemes described herein, but should satisfy the broadest possible scope consistent with the principles and new features disclosed herein.

Claims (54)

1. A wireless communication device, comprising: at least one processor configured to determine a system bandwidth from a set of possible system bandwidths, determine a set of subcarriers applicable to a beacon radio signal based on a system bandwidth, and generate a beacon radio signal based on a set of subcarriers ; and a storage device connected to at least one processor. 2. The device according to claim 1, in which at least one processor is configured to convert the beacon radio signal into one subcarrier from a set of subcarriers in each symbol period in which the beacon radio signal is transmitted. 3. The device according to claim 2, in which at least one processor is configured to determine a pattern for frequency hopping of the beacon signal based on the cell identifier (ID) and select one subcarrier from the set of subcarriers based on the said frequency hopping pattern beacon radio signal. 4. The device according to claim 2, in which at least one processor is configured to select one subcarrier from the set of subcarriers based on the code of the beacon signal indicating which subcarrier to use for the beacon signal in each symbol period in which the beacon signal is transmitted . 5. The device according to claim 1, in which the subcarriers applicable to the beacon signal have a predetermined diversity, the number of subcarriers applicable to the beacon signal is variable and is determined based on the system bandwidth. 6. The device according to claim 1, in which the number of subcarriers applicable to the beacon signal is fixed, and the subcarriers applicable to the beacon signal have variable spacing, determined based on the system bandwidth. 7. The device according to claim 1, in which at least one processor is configured to determine the number of beacon radio signals for transmission based on the system bandwidth. 8. The device according to claim 1, in which at least one processor is configured to generate one beacon radio signal if the system bandwidth is equal to or less than a predetermined value, and to generate a plurality of beacon radio signals if the system bandwidth is greater than a predetermined value . 9. A wireless communication method, comprising the steps of: determining a system bandwidth from a set of possible system bandwidths; determining a set of subcarriers applicable to the beacon signal based on the system bandwidth and generating a beacon radio signal based on the set of subcarriers. 10. The method according to claim 9, in which the formation of the beacon signal is that they convert the beacon signal into one subcarrier from a set of subcarriers in each symbol period in which the beacon signal is transmitted. 11. The method according to claim 10, in which the formation of the beacon signal further comprises the steps of: determining a pattern for frequency hopping of the beacon radio signal based on the cell identifier (ID) and selecting one subcarrier from the set of subcarriers based on said pattern for frequency hopping beacon radio signal. 12. The method of claim 9, further comprising determining the number of beacon radio signals for transmission based on the system bandwidth. 13. A wireless communication device, comprising: means for determining a system bandwidth from a set of possible system bandwidths; means for determining a set of subcarriers applicable to a beacon radio signal based on a system bandwidth; and means for generating a beacon radio signal based on a set of subcarriers. 14. The device according to item 13, in which the means for generating a beacon signal comprises means for converting the beacon signal into one subcarrier from a set of subcarriers in each symbol period in which the beacon signal is transmitted. 15. The device according to 14, in which the means for generating a beacon signal further comprises: means for determining a pattern for frequency hopping of the beacon radio signal based on the cell identifier (IP) and means for selecting one subcarrier from the set of subcarriers based on said hopping pattern tuning the frequency of the beacon radio signal. 16. A machine-readable medium containing instructions that, when executed by a machine, prompts said machine to perform operations including: determining a system bandwidth from a set of possible system bandwidths; determining a set of subcarriers applicable to the beacon signal based on the system bandwidth; and generating a beacon radio signal based on the set of subcarriers. 17. The machine-readable medium of claim 16, wherein the instructions, when executed by a machine, cause said machine to perform operations further including: mapping the beacon radio signal to one subcarrier from the set of subcarriers in each symbol period in which the beacon radio signal is transmitted. 18. The machine-readable medium of claim 17, wherein the instructions, when executed by a machine, cause said machine to perform operations further including: determining a pattern for frequency hopping of the beacon signal based on the cell identifier (ID) and selecting one subcarrier from the set subcarriers based on said pattern for frequency hopping of a beacon radio signal. 19. A wireless communications device, comprising: at least one processor configured to determine a system bandwidth from a set of possible system bandwidths, determine a set of subcarriers applicable to beacon radio signals based on a system bandwidth, and detect beacon radio signals based on a set subcarriers; and a storage device connected to at least one processor. 20. The device according to claim 19, in which at least one processor is configured to demodulate during each symbol period in which the beacon radio signals are transmitted to receive received symbols, determine possible subcarriers with a received signal quality exceeding a threshold, based on the received symbols and identify cells transmitting beacon radio signals based on possible subcarriers. 21. The device according to claim 20, in which at least one processor is configured to identify cells transmitting beacon radio signals, further based on patterns for frequency hopping of the beacon radio signal for various possible cell identifiers (IDs). 22. The device according to claim 20, in which at least one processor is configured to identify cells transmitting beacon radio signals, additionally based on the code of the beacon radio signal indicating which subcarrier to use for the beacon radio signal in each symbol period for each possible identifier (ID) cells. 23. The device according to claim 19, in which at least one processor is configured to detect beacon radio signals received from the entire system bandwidth, if the system bandwidth is equal to or less than a predetermined value, and detect beacon radio signals received from part system bandwidth if the system bandwidth is greater than a predetermined value. 24. The device according to claim 19, in which at least one processor is configured to perform an initial cell search based on synchronization signals transmitted by the cells and determine a system bandwidth based on system information received from the cell detected as a result initial cell search. 25. The device according to claim 19, in which the at least one processor is configured to periodically search for neighboring cells while in an idle or active state to detect beacon radio signals from neighboring cells. 26. A wireless communication method, comprising the steps of: determining a system bandwidth from a set of possible system bandwidths; determining a set of subcarriers applicable to beacon radio signals based on the system bandwidth and detecting beacon radio signals based on a set of subcarriers. 27. The method according to p. 26, in which the detection of beacon radio signals is that: perform demodulation during each symbol period in which the beacon radio signals are transmitted in order to receive the received symbols, determine possible subcarriers with the quality of the received signal exceeding the threshold value, based on the received symbols, and identifying cells transmitting beacon radio signals are identified based on possible subcarriers. 28. The method according to item 27, in which the detection of beacon radio signals further comprises identifying cells transmitting beacon radio signals, further based on patterns for frequency hopping of the beacon radio signal for various possible cell identifiers (IDs). 29. The method of claim 26, wherein detecting the beacon signals is detecting beacon signals received from the entire system bandwidth if the system bandwidth is equal to or less than a predetermined value, and detecting beacon radio signals received from part of the bandwidth system if the system bandwidth is greater than a predetermined value. 30. A wireless communication device, comprising: means for determining a system bandwidth from a set of possible system bandwidths; means for determining a set of subcarriers applicable to beacon radio signals based on a system bandwidth; and means for detecting a beacon radio signals based on a set of subcarriers. 31. The apparatus of claim 30, wherein the means for detecting beacon radio signals comprises: means for performing demodulation during each symbol period in which the beacon radio signals are transmitted to obtain received symbols,
means for determining possible subcarriers with a received signal quality exceeding a threshold value based on the received symbols; and means for identifying cells transmitting beacon radio signals based on possible subcarriers. 32. The device according to p, in which the means for detecting beacon radio signals further comprises means for identifying cells transmitting beacon radio signals, further based on patterns for frequency hopping of the beacon radio signal for various possible cell identifiers (IDs). 33. A machine-readable medium containing instructions that, when executed by a machine, prompts said machine to perform operations including: determining a system bandwidth from a set of possible system bandwidths; determining a set of subcarriers applicable to beacon radio signals based on a system bandwidth; and detecting beacon radio signals based on a set of subcarriers. 34. The computer-readable medium of claim 33, wherein the instructions, when executed by a machine, cause said machine to perform operations, further including: performing demodulation during each symbol period in which the beacon signals are transmitted to obtain received symbols; determining possible subcarriers with a received signal quality exceeding a threshold value based on the received symbols; and identifying cells transmitting beacon radio signals based on possible subcarriers. 35. The computer-readable medium of claim 34, wherein the instructions, when executed by a machine, cause said machine to perform operations further comprising: identifying cells transmitting beacon radio signals, further based on patterns for frequency hopping the beacon radio signal for various possible identifiers (ID) cells. 36. A wireless communication device, comprising: at least one processor configured to generate a wideband synchronization signal used by subscriber units (UEs) for an initial cell search, generate a narrowband beacon radio signal used by a UE to search for neighboring cells, and send Broadband synchronization signal and narrow-band beacon radio signal; and a storage device connected to at least one processor. 37. The device according to clause 36, in which at least one processor is configured to display a broadband synchronization signal in a fixed part of the system bandwidth, and a narrow-band beacon radio signal in different subcarriers in different periods of the symbol, in which a narrow-band beacon radio signal is transmitted . 38. The device according to clause 36, in which the broadband synchronization signal contains an additional synchronization signal and in which at least one processor is configured to generate an additional synchronization signal based on the pseudo-random sequence for the identifier (ID) of the cell and generate a narrow-band beacon radio signal on based on a beacon frequency hopping pattern for a cell ID. 39. The device according to clause 36, in which the broadband synchronization signal contains the main synchronization signal used by the UE to detect cells during the initial search cell. 40. A wireless communication device, comprising: at least one processor configured to perform an initial cell search based on broadband synchronization signals transmitted by cells in a wireless communication system and to search neighboring cells based on narrowband beacon radio signals transmitted by cells ; and a storage device connected to at least one processor. 41. The apparatus of claim 40, wherein the at least one processor is configured to receive wideband synchronization signals from a fixed portion of the system bandwidth and narrowband beacon radio signals from different subcarriers at different symbol periods to which narrowband beacon radio signals are transmitted. 42. The device according to clause 40, in which the broadband synchronization signals contain additional synchronization signals and in which at least one processor is configured to detect additional synchronization signals based on pseudorandom sequences for a set of possible identifiers (IDs) of the cell and narrowband beacon radio signals based on a set of patterns for frequency hopping of a beacon signal for a set of possible cell IDs. 43. The device according to clause 40, in which the broadband synchronization signals contain the main synchronization signals and in which at least one processor is configured to detect cells during the initial search for cells based on the main synchronization signals transmitted by cells. 44. A wireless communication device, comprising: at least one processor configured to generate a beacon radio signal, generate at least one synchronization signal and frequency division multiplexed beacon radio signal and at least one synchronization signal in various parts of the system bandwidth; and a storage device connected to at least one processor. 45. The device according to item 44, in which at least one synchronization signal contains an additional synchronization signal used for initial cell search. 46. The apparatus of claim 44, wherein the at least one synchronization signal comprises a main synchronization signal used to detect a cell during an initial cell search. 47. The device according to item 44, in which at least one processor is configured to convert the beacon radio signal to different subcarriers in the first part of the system bandwidth at different symbol periods in which the beacon radio signal is transmitted, and at least one a synchronization signal to the second part of the system bandwidth during symbol periods in which the beacon signal is transmitted. 48. The device according to clause 47, in which at least one processor is configured to determine the first part of the total transmit power for use for the beacon radio signal based on the first part of the system bandwidth and the second part of the total transmit power for use, for at least one clock signal based on the second part of the system bandwidth. 49. The device according to item 44, in which at least one processor is configured to determine the system bandwidth from the set of possible system bandwidths and the beacon radio signal bandwidth based on the system bandwidth. 50. A wireless communication device, comprising: at least one processor configured to receive beacon radio signals from a first part of a system bandwidth and synchronization signals from a second part of a system bandwidth, wherein the beacon radio signals and synchronization signals are frequency division multiplexed; and a storage device connected to at least one processor. 51. The device according to item 50, in which the synchronization signals contain additional synchronization signals and in which at least one processor is configured to perform an initial cell search based on additional synchronization signals and to search for neighboring cells based on beacon radio signals. 52. The device according to item 50, in which the synchronization signals contain the main synchronization signals and in which at least one processor is configured to detect cells during the initial search for cells based on the main synchronization signals and search for neighboring cells based on beacon radio signals . 53. The device according to item 50, in which at least one processor is configured to receive beacon radio signals from various subcarriers in the first part of the system bandwidth at different symbol periods in which the beacon radio signals are transmitted, and to receive synchronization signals from the second part system bandwidth during symbol periods into which beacon radio signals are transmitted. 54. The device of claim 50, wherein the at least one processor is configured to determine a system bandwidth from a set of possible system bandwidths and a beacon radio signal bandwidth based on a system bandwidth.

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