TW201014234A - Methods and systems for choosing cyclic delays in multiple antenna OFDM systems - Google Patents

Abstract

Certain embodiments of the present disclosure relate to a method to determine appropriate values of cyclic delays applied at a transmitter with multiple antennas in order to provide accurate estimation of channel gains in a multiple-input single-output (MISO) system or multiple-input multiple-output (MIMO) system.

Description

201014234 PRIORITY CLAIM The request in this case is entitled "Method and apparatus for transmitting pilots from multiple antennas" and submitted by the US Temporary on March 14, 2008 The benefit of the priority of the patent application S/N. 61/036,895, the entire disclosure of which is hereby incorporated by reference in its entirety in its entirety in the the the the the the the the the the the More particularly, it relates to a method for selecting an appropriate cyclic delay value for multi-antenna transmission in order to accurately estimate the channel gain. [Prior Art] There is still a defect in the prior art. [Summary] Some embodiments provide a wireless communication system. A method of transmitting pilots. The method generally includes generating a first pilot frequency for a first transmit antenna based on a first cyclic delay, and generating a second cyclic delay based on at least one cyclic prefix length greater than a first cyclic delay. A second pilot frequency for the second transmit antenna. 201014234

Certain embodiments provide a method of performing channel estimation in a wireless communication system. The method generally includes obtaining a first input sample comprising first and second pilot frequencies, wherein a first pilot frequency is generated based on a first cyclic delay and transmitted from a first transmit antenna, and a second pilot frequency is based on a second cyclic delay Generating and transmitting from the second transmit antenna, the second cyclic delay is greater than the first cyclic delay by at least a cyclic prefix length, and the first input samples are from the first receive antenna, and the first input samples are processed to obtain A first channel estimate of a transmit antenna and a second channel estimate for a second transmit antenna. Some embodiments provide an apparatus for transmitting a pilot frequency in a wireless communication system. The apparatus generally includes logic for generating a first pilot frequency for the first transmit antenna based on the first cyclic delay, and for generating a second transmit delay based on a second cyclic delay greater than the first cyclic delay by at least a cyclic prefix length The logic of the second pilot frequency of the antenna. Certain embodiments provide an apparatus for performing channel estimation in a wireless communication system. The apparatus generally includes logic for obtaining a first-input sample comprising first and second pilot frequencies, wherein the first pilot frequency is generated by the first cyclic delay and transmitted from the first transmit antenna, the second pilot frequency being Based on the first-cycle delay and transmitted from the second transmit antenna, the second cyclic delay is greater than the Lf delay by at least a _ prefix length 'and these input samples are from the first receive antenna; and for processing the first input samples A logic is obtained for the first channel estimate of the first transmit antenna and the first channel estimate for the second transmit antenna. Some embodiments provide an apparatus for transmitting a pilot frequency in a wireless communication system. The apparatus generally includes means for generating a first pilot frequency for a transmit antenna of the 4th 201014234 based on a first cyclic delay, and for generating a second cyclic delay based on at least * ring prefix 胄 greater than the first cyclic delay纟, means for giving a second pilot frequency to the second transmit antenna. " Certain embodiments provide an apparatus for performing channel 'estimation in a wireless communication system. The apparatus generally includes means for obtaining a first input sample comprising first and second pilot frequencies, wherein the first pilot frequency is generated based on a first cyclic delay and transmitted from a first transmit antenna, the second pilot frequency being based on a first loop delay is generated and transmitted from the second transmit antenna, the second loop delay is greater than the first loop delay by at least a cyclic prefix length, and the first input samples are from the first receive antenna; and for processing the first The input samples are obtained to obtain a first channel estimate for the first transmit antenna and a second channel estimate for the second transmit antenna. Some embodiments provide a computer program product for transmitting a pilot frequency in a wireless communication system, including a computer readable medium having instructions stored thereon, the instructions being executable by one or more processors. The instructions generally include: a first pilot frequency for generating a first transmit antenna based on the first cyclic delay, and a second cyclic delay for generating at least a cyclic prefix length greater than the first cyclic delay The second pilot frequency of the second transmit antenna. Some embodiments provide a computer program product for performing channel " estimation in a wireless communication system, including computer readable media having instructions stored thereon, the instructions being executable by one or more processors. The instructions generally include instructions for obtaining a first input sample comprising first and second pilot frequencies, wherein the first pilot frequency is generated based on the first cyclic delay and the 'second pilot frequency transmitted from the first transmit antenna is based on a second cyclic delay 201014234 and transmitted from the second transmit antenna, the second cyclic delay being greater than the first cyclic delay by at least a cyclic prefix length, and the first input samples are from the first receive antenna; and for processing These first input samples obtain an instruction for a first channel estimate of the first transmit antenna and a second channel estimate for the second transmit antenna. [Embodiment] The word "exemplary" is used herein to mean "acting as an example, instance, or exemplification." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous. Cyclic Delayed Tool Set (CDD) S can be applied to multi-antenna orthogonal frequency division multiplexing (OFDM) transmission to provide higher frequency diversity and improve error rate performance by transmitting cyclically delayed data from multiple antennas. Generate multiple artificial channel paths. An estimate of the channel gain associated with the plurality of transmit antennas can be performed at the receiver side using a known pilot or training sequence. However, in some cases, if the cyclically delayed pilot sequences match the path delays in the channel profile, the time domain channel paths cannot be completely separated at the receiver. Innocent Communication System The techniques described in this paper can be applied to a variety of frequency-frequency wireless communication systems, including communication systems based on orthogonal multiplexing. Examples of such communication systems include Orthogonal Frequency Division Multiple Access (〇FDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and the like. The 〇FDMA system utilizes Orthogonal Frequency Division Multiplexing (OFDM), a modulation technique that divides the overall system bandwidth into multiple orthogonal sub-6 201014234 carriers. These subcarriers may also be referred to as tones, bins, and the like. With OFDM, each subcarrier can be independently modulated with data. SC-FDMA systems can use interleaved FDMA (IFDMA) to transmit on sub-cuts across system bandwidth, use localized FDMA (LFDMA) on blocks consisting of adjacent subcarriers, or use enhanced FDMA (EFDMA) ) is transmitted on a plurality of blocks consisting of adjacent subcarriers. In general, modulation symbols are transmitted in the frequency domain under OFDM and in the time domain under SC-FDMA. A specific example of a communication system based on an orthogonal multiplexing scheme is a WiMAX system. WiMAX, which stands for Worldwide Interoperability for Microwave Access, is a standards-based frequency-bandwidth wireless technology that provides high-throughput frequency-bandwidth connections over long distances. There are two main WiMAX applications today: fixed WiMAX and mobile WiMAX. Fixed WiMAX applications are point-to-multipoint, enabling wideband access to, for example, households and businesses. Mobile WiMAX provides full mobility of the cellular network at bandwidth frequencies. IEEE 802.16 is an emerging standards organization that defines empty intermediaries for fixed and mobile broadband wireless access (BWA) systems. These standards define at least four different physical layers (PHYs) and one media access control (MAC) layer. The OFDM and OFDMA physical layers in these four physical layers are the most popular in the fixed and mobile BWA fields, respectively. Figure 1 illustrates an example of a wireless communication system 100 in which embodiments of the present disclosure may be employed. The wireless communication system 100 can be a broadband wireless communication system. The wireless communication system 100 can provide communication for a plurality of cellular cell service areas 102 served by each of the free radical stations 104. The base station 104 can be a fixed station that communicates with the user terminal 201014234. Base station 104 may alternatively be referred to by an access point, a Node B, or some other terminology. FIG. 1 depicts various user terminals 106 throughout system 100. User terminal '106' may be fixed (i.e., stationary) or mobile. The user terminal 〇6 can alternatively be referred to as a remote station, an access terminal, a terminal, a subscriber unit, a mobile station, a station, a user equipment, a subscriber station, and the like. The user terminal 1-6 may be a wireless device such as a cellular phone, a personal digital assistant (PDA), a palm-sized device, a wireless data modem, a laptop computer, a personal computer, or the like.

A may use various algorithms and methods for transmission between the base station 104 and the user terminal 106 in the wireless communication system 100. For example, signals can be transmitted and received between base station 1〇4 and user terminal 1〇6 according to OFDM/OFDMA techniques. If this is the case, the wireless communication system 1 can be referred to as an OFDM/OFDMA system. The communication key that facilitates the transmission from the base station 1〇4 to the user terminal 1〇6 may be referred to as the downlink (DL) 108, and facilitates communication for transmission from the user terminal φ 106 to the base station 1〇4. A link can be referred to as an uplink (UL) 11 〇. Alternatively, the downlink 丨〇8 may be referred to as a forward link or a forward channel, and the uplink 110 may be referred to as a reverse link or a reverse channel. The honeycomb cell service area 102 can be divided into a plurality of sectors 112. Sector 112 is the physical footprint within the cell service area 1〇2. The base station 104 within the wireless communication system 100 can utilize an antenna that concentrates power flow within a particular sector 112 of the cellular cell service area 102. Such an antenna may be referred to as a directional antenna. 2 shows a 201014234 example frame structure 200 for time division duplexing (TDD) mode in IEEE 802.16. When the wheel passes, each frame can span a predetermined duration, for example; in frames. Split into downlink sub-frames and uplink sub-keys = can = link and upper poles such as > ton on the frame. In general, 5 and 5 1 can cover any segment of the frame. Downlink 睹: The link subframe can be separated by a transmission transmission gap (TTG) and a reception transmission gap (RTG). Several physical subchannels can be defined. Each physical subchannel can include

Qilian can also distribute subcarrier sets across system bandwidth. It is also possible to define several logical subchannels and map them to physical subchannels based on known mappings. Logical subchannels simplify the allocation of resources.

As shown in FIG. 2, the downlink subframe may include a preamble, a frame control header (FCH), a downlink map (DL-MAP), an uplink map (UL_MAp), and a downlink. Link (dl) bursts. The preamble can carry known transmissions that can be used by the subscriber station for frame detection and synchronization. The FCH may carry parameters for receiving DL-MAP, UL-MAP, and downlink bursts. The DL-MAP may carry DL-MAP messages, which may include information elements (IEs) for various types of control information (e.g., 'resource allocation or assignment) for downlink access. The UL-MAP may carry a UL-MAP message, which may include IEs for various types of control information for uplink access. The downlink burst can carry the data to the subscriber station being served. The uplink subframe can include an uplink burst that carries the data transmitted by the subscriber station scheduled for uplink transmission. The pilot-frequency transmission techniques described in this article can be used for both multi-input and multi-input 201014234 out-of-the-middle MIMo) transmissions as well as multi-input single-output (MISO) transmissions. These techniques can also be used for pilot transmissions on the downlink as well as on the uplink. For clarity, certain aspects of these techniques are described below for pilot-frequency transmissions on the downlink in the case of a scenario. Figure 3 shows a base station 104 as one of the base stations and one of the subscriber stations in Figure 1. And a block diagram of the design of the subscriber station 106. The base station 1〇4 is equipped with a plurality of (AM solid) antennas 334a to 334m. The subscriber station 106 is equipped with a plurality of (and) antennas 352a to 352r » ' at the base station 1〇4 'transmitting (TX) data processor 32〇 may receive data from data source 312, process (e.g., encode and symbol map) the data based on one or more modulation and coding schemes, and provide data symbols. As used herein, a data symbol is a symbol corresponding to a material, a pilot frequency symbol is a symbol corresponding to a pilot frequency, and a symbol can be a real or complex value. The data symbols and pilot symbols may be modulation symbols derived from a modulation scheme such as PSK or QAM. The pilot frequency may include first checking the known data for both the base station and the subscriber station. TX MIMO processor 330 can process these data and pilot symbols and provide a stream of output symbols to slave modulators (m〇d) 332a through 332m. Each modulator 332 can process its round-out symbol stream (e.g., for implementing 〇FDM) to obtain an output sample stream. Each modulator 332 can be further conditioned (e.g., converted to analog, filtered, amplified, and upconverted) to output its sample stream and produce a downlink signal. The two downlink signals from modulators 332a through 332111 may be transmitted via antennas 33" to 334m, respectively" at subscriber station i06, where R days, lines 352 & everywhere can receive the base station 104 from base 201014234 Downlink signals, and each antenna 352 can provide the received signals to an associated demodulator (DEMOD) 354. Each demodulator 354 can be conditioned (eg, filtered, amplified, down converted, and digitally) The nickname it receives is used to obtain input samples and these can be further processed. The input samples (eg, for implementing OFDM) are used to obtain received symbols. Each demodulator 354 can provide received data symbols to μίμο. Detector 360 provides the received pilot symbols to channel processor 394. Channel processor 394 can estimate the response from the base station 104 to the user station 120 based on the received pilot symbols and provide the channel estimates to ΜΙΜ. 〇 Detector 360. ΜΙΜΟ Detector 360 can perform ΜΙΜΟ detection of the received symbol based on the ΜΙΜ〇 channel estimate and provide the detected symbol, the latter being the opposite An estimate of the transmitted data symbols. The receive (Rx) data processor 37 can process (e.g., symbol demap and decode) the detected symbols and provide the decoded data to the data slot 372. The subscriber station 106 can evaluate the channel status. And generating feedback messages that can include information of various types of φ. Feedback information and data from data source 378 can be processed by TX data processor 380 (eg, encoding and symbol mapping), spatially processed by τχΜΙΜΟ processor 382, and The modulators 35 to 354r further process to generate scaled uplink signals which can be transmitted via antennas 352a through 352r. At the base station 104, the R uplink signals from the subscriber station 106 can Received by antennas 33 to 334m, processed by demodulators 3323 to 332m, spatially processed by MIM detector 336, and processed further by Μ(4) processor 338 (eg, 'symbol de-mapping and decoding) to recover the subscriber station The feedback information and data sent by the controller 6. The controller/processor 201014234 340 can control the data transmission to the user station 基于6 based on the feedback information. The processors/processors 340 and 390 can direct the operations at the base station 1〇4 and the subscriber station 106, respectively. The memories 342 and 392 can store the data and code used by the base station 104 and the subscriber station 106, respectively. 344 may schedule subscriber station i 〇 6 and/or other subscriber stations to perform data transmission on the downlink and/or uplink based on feedback information received from all subscriber stations. IEEE 802.16 for downlink and uplink utilization Orthogonal Frequency Division Multiplexing (OFDM). OFDM divides the system bandwidth into multiple (beating) orthogonal subcarriers, which can also be called frequency modulation, frequency slots, etc. Each subcarrier can be used as data or Pilot frequency modulation. The number of subcarriers may depend on the system bandwidth and the frequency spacing between the subcarriers. For example, it can be equal to 128, 256, 512, 1024, or 2048. This total of subcarriers may only be used by a subset of its available data and piloted transmissions, while the remaining subcarriers may be used as guard subcarriers that allow the system to meet the spectral mask requirements. In the following description, the data subcarrier is a subcarrier for data, and the pilot subcarrier is a subcarrier for pilot frequency. The OFDM symbols can be transmitted in each OFDM symbol period (or simply symbol period). Each OFDM symbol may include a data subcarrier to transmit data, a pilot frequency subcarrier to transmit a pilot frequency, and/or a guard subcarrier not used for data or pilot. Figure 4 shows a block diagram of a design of an OFDM modulator 4A that can be included in each of modulators 332a through 332m and modulators 354a through 354r in Figure 3. Within OFDM modulator 400, symbol-subcarrier mapper 410 receives the output symbols and maps them to a total of one subcarrier. In each OFDM symbol period, unit 412 inversely transforms (I) the I output symbols corresponding to the total of ~ subcarriers by discrete Fourier transform 12 201014234, to the time domain and provides a K-fixed time domain. A useful part of the sample. Each sample is a complex value to be transmitted in one chip period. The _ (μ) converter 414 serializes this sample in the useful portion. The loop prefix generator 416 copies the last ^> samples of the useful portion and appends the ^ samples to the front of the useful portion to form a sample containing

OFDM symbol. Each 〇FDM symbol thus contains a useful portion of 样本^ samples and a cyclic prefix with 1 sample. The cyclic prefix is used to combat inter-symbol interference (ISI) and inter-carrier interference (ICI) due to delay spread in the wireless channel. Back to Figure 3, on the downlink, the MIM〇 channel is used by the base station 1 The one of the transmitting antennas at the 〇4 and the receiving antennas at the subscriber station 1〇6 are formed. The chirp channel is formed by a single-input single-output (sis〇) channel or each possible transmit and receive antenna to an SIS〇 channel. The channel response for each SISO channel can be characterized by either a time domain channel impulse response or a corresponding φ frequency domain channel frequency response. The channel frequency response is the discrete Fourier transform (DFT) of the channel impulse response. The channel impulse response for each SISO channel can be characterized by £ time domain channel taps (channel taPs), where Z is typically much smaller. * That is, if a pulse is applied at the transmit antenna, the L time-domain samples at the sample rate at the receive antenna with respect to the impulse excitation will be sufficient to characterize the response of the SISO channel. The number of channel taps (L) required for channel impulse response depends on the delay spread of the system, which is the time difference between the earliest and latest signal instances with sufficient energy arriving at the receive antenna. 13 201014234 Each SISO channel may include one or more propagation paths between the transmit and receive antennas corresponding to the SIS channel, where these propagation paths are determined by the wireless environment. Each path can be associated with a particular complex gain and a specific delay. For each SISO channel, the complex gain of the Z channel taps is determined by the complex gain of the SISO channel gates. Each SISO channel therefore has a channel perspective with paths 4 to (where the complex gain of each path 4 can be zero or non-zero. Cyclic delay diversity (CDD) can be used to establish frequency diversity in MIMO transmission, This can improve error rate performance. With cyclic delay diversity, the OFDM symbols for each transmit antenna can be cyclically delayed as described below. Different amounts of different cyclically delayed signals can be transmitted from the M transmit antennas. However, 'Jutah delay diversity may adversely affect the ΜΙΜΟ channel estimation in some cases. In particular, 'if the cyclically delayed signal matches the path delay in the channel perspective, it may not be possible to separate the paths ❿ 1 eg, It may not be possible for a given receive antenna to determine that the complex gain corresponding to 2 delays is due to (i) a transmission signal from a transmission day without cyclic delay and via a path with 2 samples delay (four), and also () From a transmit antenna with a 1-sample cyclic delay [and via a downlink signal received with a (one) 篥 = late path, the (10) is derived from a 2-ring delay Passing the antenna 2 and receiving the dip link signal via the path without delay. The second pass of the line: has the path (4) and if it comes from this launch day, the second: the letter: has a delay of '. The Z channel taps of each 201014234 SISO channel can be determined unambiguously in the case where all values of the cable are different, where / = 0"." £_!, W = , 7; is the duration of the useful part and equals the sample 'and 'mod' indicates the modulo operation. This condition also applies to full frequency • reuse. - For some embodiments, each transmit antenna (with 0 The cyclic delay of the one of the transmit delays of the cyclic delay can be selected to be equal to or greater than the maximum expected delay spread in the system. The loop prefix length ^^ can be selected to be equal to or greater than the maximum in the system. It is expected that the delay will open. Thus, 1. Thus, for some embodiments, the cyclic delay for each transmit antenna can be selected as follows: m 9 m = - 1 /1 Λ i^OV ^ where meaning. 'And ν&1, . Figure 5 Shows that (1) is a cyclic delay diversity in an exemplary case where 乂. = 0 and for / = 1, from 1 to ^ = ^, where M = 4 transmit antennas. The transmit antenna 〇 has 0 Cyclic delay, and for the transmit antenna, the useful part_minute is cyclically shifted ~ delayed by G samples. The transmit day ^ has a cyclic delay of ^, and for the transmit antenna, the useful part is cyclically shifted by ^^ The transmitting antenna 2 has a cyclic delay of 2·ΛΤ, and for the transmitting antenna, the useful portion is cyclically shifted by one hundred samples. The transmitting antenna 3 has a cyclic delay of Μ, and for the transmitting antenna, a useful part The samples are cyclically shifted by the number of samples. The cyclic delay for the two transmit antennas according to equation (1)' can be

Ex , 15 201014234 tm+l _ 言 m Ncp ′ ^ ~ ..M ~ 2 , ( 2 ) Simultaneous k-l & NfPT - NCp. The design of this type of beekeeping in equation (2) is different for all values of 4 pairs and w. Thus an unambiguous channel estimate (which is referred to as full channel estimation) for all /; strip paths from all of the transmit antennas becomes possible. If the cyclic delays for the two transmit antennas are normalized or known a priori, there is no need to explicitly send a command for these cyclic delays. The base station 104 can transmit pilot symbols from the transmit antennas in a tricky manner that assists the subscriber station 6 in performing full channel estimation. The pilot frequency symbol can be transmitted on the 5 subcarrier cores to 1 , where in general. These $ pilot subcarriers can be determined as described below. You can define a set of 0 = iVC m coefficients as follows: m-0 bq = e-JMd^i^Ts , (3) where W = 〇"-.H, / = 0,... is small and, = /.Af + m = O,""0-l, and \ is the first coefficient in the set. Because, there may be less than ^

Channel taps. Thresholding can be used to zero out the non-existing channel taps. Bf ··· ^Ql Kk' Kk' b2k, ... B = K; ...bQ_'h h1^' b^' b2ks·'...Ql J whose center=3⁄4' is the z-th row of matrix B The element in , where ί = 〇, 5 and ¢ = 0,.,.,04. (4) 16 201014234 The sufficient condition for the full channel estimation is that the rank of matrix B is equal to the factory slave. This derives the necessary conditions for each, which means that w should be different for the case of [modulo. The system can operate with full frequency reuse, and each cellular service area can be transmitted on all of the totals; sub-carriers (except for protection subcarriers). For full frequency reuse, the pilot symbols can be transmitted on each subcarrier that can be used for transmission, or ie, and the matrix Β can have V:

The following form of SxS Vandermonde matrix - 1 1 1 ... 1 1

(5) For full-frequency reuse, the necessary conditions to be different are sufficient to allow full channel estimation. Even though some subcarriers are reserved for protection, all other subcarriers are used and there are more than 2 such subcarriers, whereby the matrix V will be full rank. The system can operate with partial frequency reuse and each honeycomb cell service area can be transmitted on a subset of a total number of subcarriers. For example, in the case of a partial frequency reuse factor of three, each cellular cell service area can be transmitted on about one third of a total of subcarriers. For partial frequency reuse, the pilot symbols can be transmitted on a subset of the total number of subcarriers, which can be a submatrix of the Vandermonde matrix, and the necessary conditions for % different are perhaps insufficient. However, the S pilot frequency subcarriers can be selected such that the necessary conditions are sufficient for achieving full channel estimation. 17 201014234 For some embodiments, the $ 彳丨 pilot subcarriers may be separated by p subcarriers, where p 疋 cannot divide the prime number by %^. These pilot frequency subcarriers can be selected as follows: -, -▽,···, with -▲, / where ~ is the index of the second pilot frequency subcarrier, 5· = |_~Λρ" and "L" The standard is not the limit (fl〇or). Fig. 6 shows an example pilot frequency subcarrier structure for one symbol corresponding to the design shown in equation (6). In this example, ρ = 3 and each pilot frequency i carrier is separated by a brake carrier. The pilot symbols can be transmitted on subcarriers 〇, 3, 6 to use the same pilot frequency! carrier set for each of the slave transmit antennas, as shown in FIG. The FDM symbols with these pilot frequency subcarriers can be used for the preamble shown in Figure 2 or some other sink (10) symbol. f is not in the design of equation (6), the matrix b is composed of the w van dermond matrix when the 兀 〇 . . . 备 备 备 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且 且It is composed of any element of each element. Thus the full channel estimation becomes possible under the following conditions: All values of . . . should be different, and 2. The number of rows u in matrix B is equal to or greater than Column or S 2 0. If P is a quality condition that cannot be divided by the heart ^, regardless of the length of the hexagram prefix ^ / state, the above maximum value can be satisfied (D may be subject to the total number of subcarriers (4), the number of transmitting antennas 18 201014234 The limits of the target (pair) and pilot frequency subcarrier spacing (/7) are as follows:

Ncp-max = ρ·Μ. (7) For example, for =!〇24 and P=3, =17〇. For this example, you can choose a loop prefix length of 128. As another example, for the case of Μ 2 = 1024 and Ρ = 3, the meaning is ~* = 85. For this example, you can choose a loop prefix length of 64. As a further example, for the case of =2, I· and P 5 , ^ _ =1 〇 2. For this example, you can choose a loop prefix length of 64. The pilot frequency subcarrier A interval can be selected based on the length of the cyclic delay applied on the I^ transmit antennas and the total number of subcarriers as follows:

W Μ-\ Σ^〇 ▲ Figure 7 shows a phased block diagram of the modulators 332 & 332m at the base station l〇4 of Figure 3. For the sake of simplicity, circle 7 is only shown as a process for generating a pilot frequency for this transmit antenna. In the modulator for the transmit antenna G, the symbol-subcarrier mapper 710a maps the pilot symbols to the pilot subcarriers s (eg, 'as shown in equation (6)) and maps the number of the signals. To the remaining carriers. The IDFT single % 712a performs ~point IDFT on the L pilot and zero symbols and provides four time domain samples. The p/s converter will use the ~input string I for some embodiments of the 'cyclic delay unit 716& and the ^ samples are the transmit antennas. Samples. The cyclic prefix generator 718a appends the cyclic prefix and provides an OFDM symbol including the first pilot to the transmit antenna (4). Modulator 332b may similarly generate an OFDM symbol comprising pilots for the transmit antenna. However, this is the transmit antenna 1 cyclic shift element cyclic delay unit 716b which will take these 4 samples & Each of the remaining modulators 332 can similarly generate an OFD strict symbol including the pilot frequency of its transmit antenna but can use the I samples as the transmit bit samples, where w = 01 M_b antenna / «loop shift Figure 8 shows the design of the process of m (M) 导 or MIM 〇 system production (four) pilot. Process 800 may be performed by base station ι 4 for piloted transmission on the downlink link, by user @1〇6 for piloted transmission on the uplink key' or by some other entity. The first pilot frequency to the first transmit antenna may be generated at 810' based on a first cyclic delay, such as a cyclic delay of zero samples. In (4), the first pilot frequency sequence for the mth transmit antenna may be generated based on the mth cyclic delay of the length of the cyclic delay length greater than the length (4)) of the cyclic prefix length ^, the first one for some embodiments' The cyclic delay for each of the transmitting antennas is as shown by equation (1), where meaning. =0 and for m Bu • More pilot frequencies for more transmit antennas can be generated based on the appropriate cyclic delay. At _, the first sample sequence including the first pilot frequency can be generated and = late-cycle delay. The first OFDM symbol including the first pilot frequency and having the first cyclic delay may be based on the cyclically delayed first-sample sequence to generate a first sample sequence including the first pilot frequency at 820' and cyclically delay the fourth A ring delay, where w> includes a first pilot frequency and a continuation symbol having a fourth ring delay may be generated based on a sequence of w samples through a cyclic delay 20 201014234, where w > For the first 〇fdM symbol, the pilot symbols can be mapped to the subcarriers of the neighboring cell, where p can be a prime number that cannot be divisible. For the Wth OFDM symbol, the pilot symbols can be mapped to the subcarriers separated by /7, which speaks >1. The same pilot frequency subcarriers • Sets can be used for all OFDM symbols. The number of pilot subcarriers (s) may be equal to or greater than M.iVCP. The pilot frequency subcarrier spacing (p) can be selected as shown in equation (8). The subscriber station 106 can derive a channel estimate for each of the ji/. and SISO channels in the ΜΙΜΟ channel between the base station 1〇4 and the subscriber station 1〇6. For each receive antenna, the subscriber station 1〇6 can obtain s received pilot symbols from the $ pilot 4 carriers and can remove the pilot modulation to obtain the $ pilot subcarriers for $ View. Test. The S observations of each receiving antenna y can be expressed as: yj = Bhy +n » (7) where y is the 5χ1 observation direction of the s pilot frequency subcarriers on the receiving antenna j, and B is the equation (4) The 仏ρ matrix defined in , h is the 0X1 channel gain of this slave transmit antenna, 1 quantity, and n is the noise vector. The vector h includes the element 乂. To,. before…. % elements, • to heart ~-1 is the channel benefit of transmitting antenna 0, then the next element J^Co ^ ^'^c.o+^ci-! is the channel gain of transmitting antenna 1, and so on And the last element; to 'correction' is about the channel gain from the transmit antenna. The estimation of H, can be obtained from ~ based on various techniques. In a design, the estimate can be obtained from yy based on the 21 201014234 class such as the Minimum Mean Square Error (MMSE) technique, as follows: hy=D[B^B + a^I] 'B#yy » (1〇) Where D = diagUBeB + <irBHBrl, and an estimate. The same process can be performed for each receive antenna to obtain one channel estimate for one of the SISO channels between the antenna and the receive antenna. Figure 9 shows the square circle of the design of the channel estimator 9A. In the channel estimator 900, the unit 91 obtains five received pilot symbols corresponding to the five pilot frequency subcarriers from the receiving antennas π to π-1, respectively, to 91 〇r. Each unit 910 removes the S receipts from its receiving antenna?引 pilot frequency modulation on the pilot symbol and provide an observation. The pilot frequency modulation removal can be achieved by multiplying each received pilot frequency symbol by the complex conjugate of the transmitted pilot frequency symbols. The channel estimators 912a through 912r receive $ observations from cells 910a through 91〇r, respectively. Each channel estimator 912 derives an estimate of the sum with respect to its receiving antenna, for example as shown in equation (1), and provides t. /? Decomplexer (Demux) 91 blunt to 91 deductions respectively receive from the channel estimators 912a to 912r 6 / each demultiplexer 914 solves the channel benefits in the multiplex and provides for these M transmissions M channel estimates for the antenna. Figure 1A shows a design of a process for performing channel estimation for a MISO or ΜΙΜΟ system. Process 1000 may be performed by subscriber station 1 〇 6 for downlink-to-link channel estimation, performed by base station 104 for uplink channel estimation, or by some other entity. At 1010, a cyclically delayed pilot frequency sequence may be transmitted from a similar transmit antenna, wherein the first pilot frequency sequence is based on a length wth (H)th cyclic delay length that is at least a large w th cycle delay of the cyclic prefix length I (W = 1..., M) to cycle delay. 22 201014234 At 1020, received samples can be processed for a common receive antenna to obtain an estimated channel gain for each of the utilized transmit antennas. In general, received samples can be obtained from any number of receive antennas and processed to obtain channel estimates for any number of transmit antennas for each receive antenna. At 1020, the received samples can be processed to obtain observations of the pilot frequency subcarriers, such as by (1) performing OFDMW tuning on the received samples to obtain received pilot symbols corresponding to the pilot frequency subcarriers and (ii) These receive pilot frequency symbols remove pilot frequency modulation to obtain observations of these pilot frequency subcarriers for this processing. These observations can be processed (e.g., based on the MMSE technique as shown in equation (丨0)) to obtain channel estimates for all utilized transmit antennas. The various operations of the above described methods can be performed by various hardware and/or software components and/or modules corresponding to the device plus functional blocks illustrated in the drawings. For example, block 810_82A illustrated in Figure 8 corresponds to device plus function blocks 810A-820A shown in Figure 8A. Similarly, blocks 1010-1020 illustrated in Figure 1A correspond to the device plus function blocks 1010A-1020A illustrated in Figure 1A. More generally, where the method of Figure Illustrated has corresponding counterparting means plus functional figures, the operational blocks correspond to means and functional blocks having similar numbers. The various illustrative logic blocks, modules, and circuits described in connection with the present disclosure may be implemented by general purpose processors, digital signal processors (DSPs), dedicated accumulation circuits (ASICs), field programmable gate arrays (fpga), or others. Program logic devices (PLDs), individual gate or transistor logic, individual hardware components, or any combination thereof designed to perform the functions described herein are implemented or 23 201014234. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computational impairments, such as in combination with a microprocessor-(four), a plurality of microprocessors, one or more k-processors that cooperate with a DSP core, or any other such configuration. The steps of the method or algorithm described in connection with the present disclosure can be implemented directly in hardware, in a software module executed by a processor, in a combination of the two. The software module can reside in the art. Any form of storage medium. Some examples of storage media that can be used include random access memory (RAM), read only memory (ROM), flash memory, EPROM memory, EEPR〇M _, temporary storage , hard disk, removable disk, CD-ROM, etc. The software module can include a single instruction, or many instructions, and can be distributed over several different code segments, distributed between different programs, and across multiple A storage medium may be coupled to the processor to enable the processor to read and write information from/to the storage medium. In the alternative, the storage medium may be integrated into the processor. The disclosed methods include one or more steps or actions for achieving the described methods. The method steps and/or actions can be interchanged with one another without departing from the scope of the claims. In other words, unless The specific order of the steps or actions 'others' or the order and/or use of the specific steps and/or actions may be modified without departing from the scope of the claims. The functions described may be in hardware, software, ship, or any of them. Implemented in the board. If implemented in software, each function can be stored as a single or more instructions on the computer readable medium. The storage medium can be any available media that can be accessed by the computer 24 201014234. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPR〇M, CD r〇m or other optical disk storage, disk storage or other disk storage device, or can be used to carry 'or store Any other media in the form of a command or data structure that can be accessed by a computer. Disks and optical discs used in this document include compact discs (CDs), laser discs, compact discs, and digital versatile discs. (dvd), floppy disk, and Blu-ray 8 discs, in which disks are often magnetically reproduced, and optical discs are optically reproduced by laser. Yu software or commands can also be used. Transmitted on the media. For example, if the software is using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, from the evaluation website, server, or Where other remote sources are transmitted, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the transmission medium. It will be appreciated that the φ modules and/or other appropriate means for performing the methods and techniques described herein may be downloaded and/or otherwise obtained by a user and/or a base station, where applicable. For example, such a device may Coupled to a server to facilitate forwarding of means for performing the methods described herein. Alternatively, the various methods described herein may be via a storage device (eg, RAM, ROM, such as a compact disc (CD) or floppy disk) a physical storage medium or the like, such as provided, such that once the storage device is coupled to or provided to the user terminal and/or the base station, the device can Get a variety of methods. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized. 25 201014234 It should be understood that the claims are not limited to the precise configurations and components exemplified above. Various modifications, changes and variations can be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS In the following, a more detailed description of the above brief summary may be made by way of example embodiments, in which FIG. It is to be understood, however, that the appended claims are in the FIG. 1 illustrates an example wireless communication system in accordance with certain embodiments of the present disclosure. 2 illustrates an example orthogonal frequency division multiplexing/orthogonal frequency division multiplexing access (OFDM/OFDMA) frame for time division duplexing (TDD), in accordance with certain embodiments of the present disclosure. FIG. 3 illustrates an example transmitter and an example receiver that may be used within a wireless communication system, in accordance with certain embodiments of the present disclosure. 4 illustrates a block diagram of a design of an OFDM modulator in accordance with certain embodiments of the present disclosure. FIG. 5 illustrates an example of cyclic delay diversity in accordance with certain embodiments of the present disclosure. FIG. 6 illustrates an example pilot frequency subcarrier structure for an OFDNl symbol 26 201014234, in accordance with certain embodiments of the present disclosure. Figure 7 illustrates a block diagram of a design of a modulator at the base station of Figure 3, in accordance with certain embodiments of the present disclosure. - Figure 8 illustrates a process for generating pilot frequencies for a multiple input single output (MIMO) or multiple input multiple output (MIMO) system, in accordance with certain embodiments of the present disclosure. FIG. 8A illustrates example elements that are capable of performing the operations illustrated in FIG. 9 illustrates a block diagram of a design of a channel estimator in accordance with certain embodiments of the present disclosure. Fig. 10 illustrates a process for performing channel estimation in a (d) 〇 or ΜΙΜΟ system according to (4) of the present phase. Figure 10A illustrates an example component that has the ability to perform the operations illustrated in Figure 10. [Main component symbol description] 100 wireless communication system ♦ 1 蜂 2 cellular cell service area 104 base station 106 user terminal 108 downlink 110 uplink 112 sector 312 data source 320 TX data processor 27 201014234 330 ΤΧ ΜΙΜΟ processor 340 controller / processor 342 memory - 344 scheduler, 339 data slot 338 RX data processor 336 ΜΙΜΟ detector 360 ΜΙΜΟ detector call 370 RX data processor 372 data slot 378 data source 380 ΤΧ data processor 382 ΤΧ ΜΙΜΟ processor 390 controller/processor 392 memory φ 394 channel processor 410 symbol-subcarrier mapper 412 NFFT-point IDFT • 414 parallel-serial (P/S) converter - 416 loop prefix generator 710a Symbol-subcarrier mapper 712a NFFT-point IDFT 714a P/S converter 716a cyclic delay Nc, one sample 28 201014234 718a cyclic prefix generator 718a RF unit 710b symbol-subcarrier mapper 714b NFFT - point IDFT7 1 2b P/S converter. 716b cyclic delay Nc.o+Nc,! Sample

718b cyclic prefix generator 718b RF unit 710m symbol-subcarrier mapper 712 712m NFFT - point IDFT 714m P/S converter 71 6 m cyclic delay ^ samples m=0 718m cyclic prefix generator 718m RF unit 910a shift In addition to pilot frequency modulation 912a channel estimator (eg, MMSE) 914 914a demultiplexer 910b remove pilot frequency modulation 912b channel estimator (eg, MMSE) 914b demultiplexer '910r remove pilot frequency modulation 912r channel estimator (eg MMSE) 914r solution multiplexer 29

Claims (1)

201014234 VII. Patent application scope: 1. A method for transmitting a bow pilot based on a first loop in a wireless communication system, comprising: a pilot; and a first lead generated to a first transmit antenna And generating a second pilot frequency for the second «^ transmit antenna of the first less-cyclic prefix length based on the female loop delay delayed by the first loop. 2. If the request item 1 is based on the second loop, the loop delay is generated, and the third "request item: method: the antenna antenna" is generated from at least the length of the loop prefix. The delay of the heave of each transmit antenna is /*0 where meaning, .> 0,V/ 2 J,# transmit antenna μ, and λγ υ(4) ring prefix length, "is...^_b...in transmitting... Cyclic delay, 4. As in the method of claim 1, the I second loop delay is equal to or greater than the loop: first: the ring delay is zero, and the first does not borrow 5 by = 22 method 'where the first and second jujube The method of claim 1 wherein the generating the first pilot frequency comprises: a knee-to-poor & first sequence of the first pilot frequency; and "the same sequence of delays delays the first quarantine = The step of :r pilot includes generating - a first sample sequence comprising the second pilot frequency and delaying the second sample sequence by the second cycle 30 201014234 delay. 7. The method of JS 1 π 1 wherein the step of generating a first pilot frequency comprises generating a first OFDM symbol comprising a neon silver pilot frequency and having the first cyclic delay, and Q 4 and wherein the generating second The step of piloting includes generating, for a second OFDM, a step of 4 μF, wherein the second 〇FDM symbol includes a second pilot frequency and has a first φ delay. 8. The method of claim 6, wherein the step of generating the first OFDM symbol comprises mapping the leading n 秘 nJ> A φ neck number to a subcarrier separated by /7, wherein the household is a prime number that cannot divide Ym· , B B β and ^ r are an FFT size for the first OFDM symbol. 9. The method of claim 7, wherein the step of generating the second OFDM symbol comprises mapping pilot symbols to subcarriers separated by /. The method of claim 8, wherein the 5' pilot symbols are mapped to the same set of subcarriers for both the first and second OFDM symbols. 11. The method of claim 7, wherein: /» 〇 wherein 5 is the number of subcarriers with f pilot symbols, Μ is the number of transmission days. The number is 'and the length of the cyclic delay for transmitting antenna m , w = 〇,...,Af —1. 12. The method of claim 7, wherein: Σ^〇/-〇 where Μ is the transmitting antenna (four), and ^ is the length of the cyclic delay for transmitting the antenna w / =0, by hand... #^. 31 201014234 13 - A method for performing channel estimation in a wireless communication system, comprising the steps of: obtaining a first input sample comprising first and second pilot frequencies, the first pilot frequency being generated based on a first cyclic delay and The second pilot frequency sent from the first transmit antenna is generated based on the second cyclic delay and transmitted from the second transmit antenna, the second cyclic delay being greater than the first cyclic delay. Looping a first length, and the first input samples are from a first receive antenna; and calling the first input samples to obtain a first channel estimate for the first transmit antenna and for the second transmit antenna A second channel estimate. 14. The method of claim 13 further comprising: obtaining a second input sample comprising the first and second pilot frequencies, the second input samples being from a second receive antenna; and processing the second The input sample is obtained to obtain a third channel estimate for the first transmit antenna and a fourth channel estimate for the second transmit antenna. • 15. The method of claim 13 'Processing the first-round samples includes: processing the first-input samples to obtain observations of the pilot frequency subcarriers; and processing the observations to obtain the 16. The method of claim 15, the step of obtaining an observation comprises: first and second channel estimation. The processing of the first round-in samples to perform the solution H on the I-round human samples corresponds to the _丨_胄 of the pilot-sequences; removing the boot from the received pilot symbols by μ k ' Frequency modulation to obtain the observation of the pilot frequency subcarriers such as 32 201014234. 17. The method of claim 15, wherein the step is based on a minimum mean square error (MMSE) technique ^ observation step package * the first and second channel estimates. Processing the arguments to obtain '18. The method of claim 15, wherein the /7, wherein the IN pilot subcarriers are separated by P疋 cannot divide the prime number of ^r, and the FFT size of the number. 1 is a method for OFDM 19 as claimed in claim 14, the steps of the method comprising: ???, the second input samples processing the second input samples and the observation of the 5 丨 pilot subcarriers; These observations obtain the third and fourth channel estimates. To obtain the method of 2=request item 19, wherein the step of processing the second input samples to obtain an observation comprises: introducing a second round-in sample to perform a chic demodulation to obtain corresponding to the φ. pilot frequency subcarriers Receiving the pilot frequency symbols; and removing the pilot frequency modulation from the received pilot symbols, such as the #cage, to obtain the observation of the pilot frequency subcarriers. . Jt. The method of claim 19, wherein the step of processing the observations, the Mean Square Error (MMSE) technique is used to process the observations to obtain the third and fourth channel estimates. 2. The method of claim 19, wherein the pilot subcarriers are separated by a corpse, wherein P is a prime number that does not divide by #, and is an FFT size for the 〇fdm symbol. 33 201014234 23. Apparatus for transmitting a guiding cheek in a wireless communication system comprising: - a logic for generating a first pilot frequency based on a first cyclic delay to a first transmit antenna; and - using A logic for generating a second pilot frequency for a second transmit antenna is generated based on a second cyclic delay that is greater than the first cyclic delay by at least one cyclic prefix length. The device of claim 23, further comprising: ???said for generating a third pilot frequency for a third transmit antenna based on a first cyclic delay that is greater than the second cyclic delay by at least the length of the cyclic prefix logic. 5. The apparatus of claim 23, wherein the cyclic delay for each transmit antenna is m. >〇' For, there is ^ is the length of the loop prefix, ❿7^ is the transmit antenna index, and ~ is the cyclic delay for the transmit antenna m, /w = 0,1,..., jj/ -1 〇 6. The apparatus of claim 23, wherein the first loop delay is zero and the first loop delay is equal to or greater than the loop prefix length. The apparatus of claim 23, wherein the first and second cyclic delays are not transmitted by the command. 28. The apparatus logic of claim 23, comprising: wherein the data for generating the first pilot frequency 34 201014234 is used to generate a logic comprising a first sample sequence of the tuner-inducing pilot; and a logic for delaying the first cycle of the sequence to delay the first cycle; and wherein the logic for generating the 篦-2丨檐Λ-guide frequency includes: ^ 帛 产生A logic comprising a second sequence of samples of the second pilot frequency and logic for delaying the second sequence of samples by the second cyclic delay. 29. The apparatus of claim 23, wherein the logic for generating the first pilot frequency comprises logic for generating a first QFDM symbol comprising the first pilot frequency and having the first hypochronous delay, and wherein The logic for generating the second pilot frequency includes logic for generating a second 〇FDM symbol including the second pilot frequency and having the second cyclic delay. 3. The apparatus of claim 28, wherein the logic for generating the first OFDM symbol comprises a logic for mapping pilot symbols to subcarriers separated by p, wherein Ρ is a prime number that cannot be divisible, and JVFiT is the j7FT size for the first OFDM symbol. 31. The apparatus of claim 29 wherein the logic for generating the second 〇fdm symbol comprises a logic for mapping pilot symbols to subcarriers spaced apart by 7. 32. The apparatus of claim 30, wherein for both the first and second OFDM symbols, the pilot symbols are mapped to the same set of subcarriers. 33. The apparatus of claim 29, wherein: 35 201014234 W-1, /» wherein iS is the number of subcarriers having pilot symbols 'from the number of transmit antennas, and the text is for transmitting antennas The length of the cyclic delay, /»0 w = 〇,...,Af~i 〇34. The device of claim 29: Where 舨 is the number of transmit antennas and is the length of the cyclic delay used to transmit antenna m, /w = 0,..., M-l. 35. An apparatus for performing channel estimation in a wireless communication system, comprising: logic for obtaining a first input sample comprising first and second pilot frequencies, the first pilot frequency being based on a first cyclic delay Generating and transmitting from a first transmit antenna, the second pilot frequency is generated based on a second cyclic delay and transmitted from a second transmit antenna, the second cyclic delay being greater than the first-cycle delay At least - a cyclic prefix length, and the first input samples are from a first receive antenna; and 'for processing the first input samples to obtain a flute-channel estimate for the first shot and for the first The logic of a second channel estimation of the two transmit antennas. 36. The apparatus of claim 35, further comprising: for obtaining second input sample logic comprising the first and second pilot frequencies, the cage-AA homing the first input sample from a second receive antenna; And processing the second input samples to obtain a logic for the third channel of the first transmit antenna 36 201014234 and a logic for a fourth channel of the second transmit antenna, such as the device of claim 35, Wherein the logic for processing the second input samples comprises: 'logic for processing the first input samples to obtain observations of pilot frequency subcarriers; and for processing the observations to obtain the first sum The edge of the second channel estimate. 38. The apparatus of claim 37, wherein the logic for processing the first input samples to obtain an observation comprises: performing OFDM demodulation on the first input samples to obtain a corresponding pilot frequency pair Logic of receiving a pilot symbol of a carrier; and logic for removing pilot frequency modulation from the received pilot symbols to obtain an observation of the pilot subcarriers. 39. The apparatus of claim 37, wherein the logic for processing the observations comprises for processing the observations based on a minimum mean square error (MMs magic technique to obtain the first and second channel estimates) Logic. The apparatus of claim 37, wherein the pilot subcarriers are separated by a corpse, wherein the eve is a prime number that cannot be exhausted and is used for the FFT size of the FDM symbol. 41. The apparatus of item 36, wherein the logic for processing the second input samples comprises: logic for processing the second input samples to obtain observations of pilot frequency subcarriers; and 37 201014234 for processing the observations The apparatus of claim 41, wherein the apparatus for processing the second round of samples to obtain an observation comprises: for: Performing a sample M demodulation to obtain logic corresponding to received pilot symbols of the pilot frequency subcarriers; and, for removing pilot frequency modulation from the received pilot symbols to obtain the bootstrap Frequency Chang Logic of observation of the carrier 丨 43. The apparatus of claim 41, wherein the logic for processing the observations comprises processing the observations based on a minimum mean square error (MMSE) technique to obtain the third sums The logic of the fourth channel estimation. 44. The apparatus of the monthly finding 41 are separated by the pilot subcarriers, where P is a prime number that cannot be divisible, and is the FFT size for the 〇FDM symbol. Means for transmitting a pilot frequency in a wireless communication system, comprising: means for generating a first pilot frequency for a first-transmitting antenna based on a first-exposure delay; and for using the first The loop delay is greater than at least a loop-length-first loop delay to generate a second pilot frequency for a second transmit antenna. 46. As claimed in claim 45, the step further comprises: Generating a third pilot frequency to a third transmit antenna based on a second cyclic delay that is greater than the second #ring delay by at least the cyclic prefix length. Ο·If the request is determined, Which is used for each delay Do not 'the loop of the antenna m' where 'the weight is in v/y, there is, 'is the loop word, and it is said that the transmitting antenna cable bow G is a cyclic delay for sending a 'degree' -0,1..., 4: The apparatus of claim 45, wherein the first loop delay is zero, and the second loop delay is equal to or greater than the loop prefix length. w 49. The apparatus of claim 45, wherein the first loop is a core The delay is not hunted by the command. 5〇. The device of claim 45, wherein the generating of the first reference includes: generating a first sample including the first pilot frequency a means for sequence; and, means for cyclically delaying the first sequence of samples by the first cyclic delay; and//using means for generating a second pilot frequency comprising generating a frequency comprising the reference Means of the second sample sequence and means for delaying the second sample sequence by the second loop_. 51. The apparatus of claim 45, wherein the means for generating a first pilot frequency comprises: means for generating - a first OFDM symbol comprising the first pilot frequency and having the first timing, and wherein The farm for generating the second 39 201014234 pilot frequency includes a flank for generating a second OFDM symbol including the second bow pilot and having the second cyclic delay. 52. The apparatus of claim 50, wherein the means for generating the first OFDM symbol comprises means for mapping pilot symbols to subcarriers separated by p, where P is a prime number that cannot be divisible, And is the FFT size for the first OFDM symbol. 53. The apparatus of claim 51, wherein the means for generating the second OFDM symbol comprises a ramp for mapping pilot symbols to subcarriers of the neighboring cell. 54. The apparatus of claim S2, wherein the pilot symbols are mapped to the same set of subcarriers for both the first and second OFDM symbols. 55. The apparatus of claim 51, wherein ··, ι=0 where $ is the number of subcarriers having pilot symbols, Λ/ is the number of transmitted celestial lines' and |~ is a loop for transmitting antenna w The length of the delay, τπ = 0,···”Μ—1 0 56. As the device of the request item η, where: ' ρ< νιετ-, y - A/-i Σ ~ where is the number of transmitting antennas, and The length of the cyclic delay of the transmitting antenna w, W = 0, ..., M-1. 57. - A device for performing channel estimation in a wireless communication system, including: 201014234 for obtaining the inclusion of the first and the a device of a first input sample of two 5 ί pilots, the first pilot frequency is generated based on a _th cyclic delay and transmitted from a first transmit antenna, the __α pilot being generated based on a second cyclic delay And the second loop delay is greater than the first loop delay by at least one loop word camp and #1 from the first length of the first input sample, and the second loop delay is sent from the second transmit antenna. From the first receiving antenna; and for processing the first-age Injecting a sample to obtain a first channel estimate for the first transmit antenna and a second channel estimate for the second transmit antenna. 58. The device of claim 57, Further comprising: an intrusion sample for obtaining a second input sample comprising the first pilot frequency of the first electric wall spear from a second receiving antenna; and for processing the first-to-one brother Input samples to obtain a third channel estimate for the first and a device for the music antenna. X - a fourth channel estimate for the transmit antenna 59. If the request item 57 is used to process the first - The device connected to A includes: ^ input samples for processing the devices of the first age measurement; and the method for obtaining the pilot frequency subcarriers for processing the observations to obtain I. Estimated 襞6〇. as requested in item 59, from β, teaches 'the means for processing the first 蚣 丄 secret to obtain observations includes · input samples for the first Private round-in samples to perform OFDM demodulation Means for obtaining received pilot symbols corresponding to the pilot frequency subcarriers of 41 201014234, means for shifting from the received pilot symbols, and observing the pilot subcarriers. Modulating to obtain the apparatus of claim 59, wherein the apparatus comprises: & I, 〇X, processing the observations for inclusion based on a minimum mean square error (mmse 以获得 to obtain the And means for estimating the second channel, wherein the pilot subcarriers are separated by a device as claimed in claim 58, wherein the means for processing the sample comprises: Processing the first input sample of the Rong-Ping W Temple to obtain an observation of the guided frequency subcarriers; and processing the observations to obtain (4) third and fourth channel estimation settings. 64. The apparatus of claim 63, wherein the means for processing the second input samples to obtain an observation comprises: performing OFDM demodulation on the two input samples to obtain a corresponding pilot frequency pair Means for receiving pilot symbols of a carrier; and means for removing pilot frequency modulation from the received pilot symbols to obtain an observation of the pilot subcarriers. 65. The apparatus of claim 63, wherein the means for processing the observations comprises processing the observations based on a minimum mean square error (MMSE) technique to obtain the third and fourth channel estimates Device. 42 201014234 is set to a prime number in which the pilot frequency subcarriers are separated by, and is used for the OFDM symbol 66. The apparatus of claim 63 wherein the household is the FFT size of the number that cannot be divided by #^. 67. A computer program for transmitting a pilot frequency in a wireless communication system a pilot command; and 68. The computer program product of claim 67, the instructions further comprising: generating a third guidance to the third transmit antenna based on a third cyclic delay that is greater than the second cyclic delay by at least the length of the cyclic prefix Frequency instructions. 69. The computer program product of claim 67, the φ cycle delay for each transmit antenna is η* Its _ iVc,. 2 0 'For 1, there is iVc; k #c/>, iVc/> is the length of the loop prefix, W is the transmit antenna index ' and G is the cyclic delay for the transmit antenna, 70· as requested The computer program product of 67 wherein the first loop delay is zero and the second loop delay is equal to or greater than the loop prefix length. 71. The computer program product of claim 67, wherein the first and second loop delays are not transmitted by the command. The instructions for generating the first 72. The computer program product of claim 67, wherein the instruction of the pilot frequency comprises: an instruction for generating a first sample sequence including the first pilot frequency; An instruction sequence loops the instruction to delay the first cyclic delay; and wherein the instruction to generate the second pilot frequency includes an instruction to generate a second sample sequence including the second pilot frequency An instruction to cyclically delay the second sample sequence by the second cycle delay. 73. The computer program product of claim 67, wherein the instruction to generate the first pilot frequency comprises instructions for generating a -0FDM symbol including the first pilot frequency and having the first cyclic delay, and wherein The instructions for generating the second pilot frequency include instructions for generating a second 〇FDM symbol including the second pilot frequency and having the second cyclic delay. 74. The computer program product of claim 72, wherein the instructions for generating the first facet symbol comprise instructions for mapping pilot symbols to subcarriers separated by ^ where P is not divisible~. The prime number, and ~ is the FFT size for the first OFDM symbol. 75. The computer program product of claim 73, wherein the instructions for generating the second OFDM symbol comprise instructions for mapping pilot symbols to sub-carriers of the day and night. 76. The computer program product of claim 74, wherein for both the first and the second symbols, the pilot symbols are mapped to the same subcarrier 44 201014234 wave set. 77. The computer program product of claim 73, wherein: s. , /-0 where S is the number of subcarriers with pilot symbols, from the number of transmitted sky-lines, and is the length of the cyclic delay used for the transmit antenna, w = 〇,...,Af-l ° 78. The computer program product of claim 73 is actually _ y ^ ΜΑ ❿ ΣΝ. ι«0 where is the number of transmit antennas and is the length of the cyclic delay used to transmit antenna w, w=0, . 79. A computer program for performing channel estimation in a wireless communication system, ηπ, comprising computer readable medium having instructions stored thereon, the instructions being executable by one or more processors and including: Means for obtaining a first input sample comprising first and second pilot frequencies, the first pilot frequency being generated based on a first cyclic delay and transmitted from a first transmit antenna, the second pilot frequency being Generating based on a second cyclic delay, and transmitting the second cyclic delay from a second transmit antenna by at least one cyclic prefix length, and the first input samples are from a first receive An antenna; and instructions for processing the first input samples to obtain a first channel estimate for the first transmit antenna and a second channel estimate for the second transmit antenna. 80. The computer program product of Kiss 79, the instructions further comprising: 45 201014234 for obtaining a second input sample containing the first and second pilot frequencies "the second input samples are from a second receive antenna and for processing the second input samples to obtain a second channel estimate for the first transmit antenna and a fourth channel estimate for the first transmit antenna for the first transmit antenna The computer program product of the monthly claim 79, wherein the instruction for processing the first input samples comprises: processing the ticker-final #丄 样本 sample to obtain an observation of the pilot frequency subcarrier The instructions 丨 and ^ are used to process the observations to obtain the gauges and the first and second channel estimates of the first- and second-channel estimates - the computer program product of claim 81, wherein the And the first input sample to obtain the observed instructions includes: the instructions for performing OFDM demodulation to obtain the received pilot symbols corresponding to the pilot frequency subcarriers; Used to The instructions that remove the pilot frequency modulation from the received pilot symbols to obtain the observations of the pilot frequency subcarriers are received. 83. If the computer program of claim 81 is arrogant, the military corps should be used to process the basins (4), (10) mean square error (MMSE) techniques to obtain observations such as - and Two-channel estimated instruction.如. The computer program product of claim 81, wherein the wave interval is /7, and the FFT size of the prime OFDM symbol is not the At ^ 丨 pilot subcarrier. The instructions for use in the computer program product 八τ涿 of claim 8 for processing the 46 201014234 second input samples include: processing the second input sample to obtain an instruction for the (four) frequency measurement; And a warfare order for processing the observations to obtain the third and fourth channel estimates, wherein the instructions are for processing the computer program product of claim 86. The second input sample is Instructions for obtaining observations include: Performing 〇FDM demodulation on the second input samples to obtain instructions corresponding to the received pilot symbols of the pilot frequency subcarriers; and... for removing pilot frequencies from the received pilot symbols Modulation to obtain an instruction for the observation of the pilot frequency subcarriers. 87. The computer program product of claim 85, wherein the instructions for processing the observations comprise processing the observations based on a minimum mean square error (mmse) technique to obtain the third and fourth channel estimates. instruction. 88. The computer program of claim 85, wherein the μ pilot subcarriers are separated by Ρ, where ρ is a prime number that cannot divide I, and is the FpT size for the OFDM symbol. 47