TW201001964A - Channel estimation device and method for orthogonal frequency division multiplexing system - Google Patents

Abstract

Channel estimation device and method for an orthogonal frequency division multiplexing (OFDM) system. The channel estimation method receives a plurality of OFDM symbols to generate channel estimation information. The channel estimation method comprises obtaining some pilot signal in a plurality of pilot signal to serve as a first pilot set according to the location of the pilot signals in a plurality of OFDM symbols; estimating the pilot signals in the first pilot set according to a first direction for generate a first estimation factor; estimating the pilot signals in the first pilot set according to a second direction for generate a second estimation factor; obtaining the estimated result of the pilot signals according to the first and the second estimation factors; and obtaining the channel estimation information according to the estimated result of the pilot signals.

Description

201001964 IX. Description of the Invention: [Technical Field] The present invention relates to a signal receiving technique in a wireless communication system, particularly relating to an orthogonal frequency division multiplexing (OFDM) system. Method and device for estimating the middle channel. [Previous technology #f] f In recent years, Orthogonal Frequency Division Multiplexing (OFDM) technology has been widely used for its advantages of high multipath interference resistance and high spectrum utilization in high-speed data transmission. Can support multiple access for multiple users. In particular, the Orthogonal Frequency Division Multiple Access (OFDM) technology combined with frequency division multiple access can more effectively control the data rate of each user, thereby improving channel utilization. For example, in the 802.16e standard, the Worldwide Interoperability for Microwave (Access) system, the physical layer introduces a combination of orthogonal frequency division multiplexing and multiple input and multiple output antennas to enable transmission. The speed can be doubled while supporting a certain mobility. It can provide non-line-of-sight data transmission with a spectrum range of 2GHz to 11GHz when the carrier bandwidth is 20MHz. The data rate can reach 75Mbps, the coverage radius is 10km, and the moving speed is the highest.玎120 km/h. However, in wireless communication systems, the transmission of data is often affected by the frequency selective fading channel and the time-varying characteristics of the channel. In the wireless terminal, it is necessary to estimate the possible influence of the above factors on the data transmission process. Especially at the signal receiving end, channel information needs to be obtained for quantization and decoding. VTU08-0002/ 0608A-A41642-TW/Final 201001964 Therefore, the method of two-way ^/古计 becomes the key to wireless data receiving processing. In the channel estimation method used, the method of obtaining the channel information by the two-dimensional dimension-wave method is based on the === tap system Perform a finite pulse back to the dirty. This method;; = reflects the time-varying characteristics of the channel and the effect of frequency selective fading. However, the filter coefficient of the Wiener filter is large. Although it can reduce the two-dimensional Wiener The number of pilot subcarriers on the complexity two still needs a large amount of computation: it is effective to obtain the coefficient related information of the Wiener wave transformer. [Inventive content] This is a guide for Orthogonal Frequency Division Multiplexing (OFDM) systems. The characteristics of the frequency Symb〇1) symbol proposes a fast and simple method for channel estimation, which solves the problem in the estimation algorithm of the financial channel. The present invention proposes a channel estimation method for an Orthogonal Frequency Division Multiplexing (OFDM) system. The method receives a plurality of orthogonal frequency division multiplexing symbols, and generates a channel estimate=beta. The method includes multiple orthogonal frequencies according to the method. And dividing a plurality of pilot signal positions in the multiplexed symbols into the first pilot, and each pilot signal in the first pilot set in the basin is a first relative bit ^· The first pilot coefficient of the first direction is calculated by the first estimation coefficient of the first pilot signal in the first direction, and the second estimation coefficient of the pilot signal in the first direction is calculated to generate a second estimation coefficient. The root-valued coefficient and the second coefficient of estimation obtain a pilot signal estimate, , , . And, according to the estimation result of the pilot signal, the channel estimation VTU08-0002/ 0608A-A41642-TW/Final 201001964 0 is sent out - the channel used in the orthogonal frequency division multiplexing system Estimating that a plurality of orthogonal frequency division multiplexing symbols are received, and generating a channel estimate for the split includes: the pilot signal selector 'for multiple pilot signal positions according to multiple books/minutes' will be The pilot signal "knife is a pilot set" where each of the first pilot sets is a first relative position; pilot '.唬 撰 ( 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 四 ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '^彳^^' according to the first-estimation coefficient and the second evaluation system, the pilot signal estimation result; and the channel fruit group, the frequency signal two sets, and the seventh type is used for orthogonal frequency The receiving and receiving data and receiving signal front-end processing module of the sub-multiplexing system is configured to receive a plurality of orthogonal frequency division multiplexing, channel estimating devices, receiving the Wei Wei JU channel estimation information, and receiving the signal according to the Channel estimation information and multiple orthogonal frequency masks are used for data decoding. The high-speed estimation device and method can greatly reduce the defects. The channel estimation technology of the existing orthogonal frequency division multiplexing system: ',, = the characteristics and advantages of this month can be more obvious and easy to understand, the following is a special

VTU0S-0002/0608A-A4J642-TW/FinaI 8 201001964 The preferred embodiment, with reference to the accompanying drawings, is described in detail below: [Embodiment] In the following drawings and embodiments, the present invention is used in microwave access. The application in the 802.16d or 802.16e version of the Global Interworking Access System is an embodiment 'and a microwave access global interworking access system in which the parent symbol includes 1 〇 24 subcarriers is taken as an example. It is to be understood that the number of subcarriers and other settings are not intended to be limited to the system, only to enable those skilled in the art to better understand the present invention, and the present invention is not limited to the microwave access global interworking access system. Any other system consistent with the conditions required by the present invention or systems having similar channel characteristics as described herein and using the methods described herein can be considered as an embodiment of the present invention.

Figure 1 is a block diagram of a wireless communication system, particularly a microwave access global interworking access receiving system. The microwave access global intercom access receiving system ι includes an antenna set 11G, an orthogonal frequency division (10) modulation module (10), a channel estimation module 130, and a post-discrimination her (10). In the microwave access global intercommunication (4) system, the antenna receiving module (4) may include an antenna array of 2 transmissions and 2 receptions, or an antenna receiving module 110 including single-issue single-receiving or multiple-receiving single-receiving, and may also include a radio frequency signal. A device that converts to a base = say, such as an analog-to-digital converter, a filter, and the like. In the microwave sub-global intercommunication receiving system, the antenna receiving module (10) outputs orthogonal = symbol and antenna discriminating information, and the orthogonal frequency division multiplexing symbol can have two I carriers and multiple user data, wherein the subcarriers Transmission includes two, off:: for the pilot signal and the data signal. When the antenna identification information packet Tianke X k antenna is a single antenna, the single antenna flag bit is YES. When transmitting VTU08-0002/0608A.A41642.TW/Final 9 201001964 antenna is multi-antenna, 'single antenna target is it no . The Orthogonal Frequency Division Multiplexing (OFDM) demodulation 12G is connected to the antenna receiving module iiQ, and the Orthogonal Frequency Division Multiplexing Demodulator 120 can be used to perform demodulation using the Fast Fourier Transform (FFT). The frequency information is sent to the channel estimation module 13G, and the data information is sent to the poor material back-end processing module M〇. The channel estimation module 13A will be described in detail later. The data backend processing module 140 receives the result generated by the channel estimation module 130 and the demodulation result of the orthogonal frequency division multiplexing demodulation module 12A. It should be noted that when the antenna receiving module 11G turns off the multi-transmitting antenna array such as 2 transmissions and 2 receptions, the data back-end processing module 14G needs to perform space-time decoding on the received data signals (STC, space_time c〇). Ding). When the antenna receiving module 11G uses a single-shot multi-receiver antenna array such as burst 2, the material back-end processing module 14 needs to perform a merge operation on the received data signals. When the antenna receiving module 〇 uses, for example, a burst antenna array, the hopper back-end processing module 14 does not need to perform data sorting or space-time decoding for the antenna array. Of course, the data backend processing module 14 can also perform quadrature phase shift keying or positive parent amplitude modulation and demodulation, hybrid automatic repeat request (HARQ, Hybrid) after decoding the channel estimation information.

Automatic Repeat request), deinterleaving, and channel decoding. Figure 2 is a schematic diagram of the channel estimation module in Figure 1. The channel estimation module, and 130 includes a V-frequency L-number selector 21 〇, an initial value calculator 220, a pilot b-number evaluation module 230, and a channel estimation information calculator 24〇. The pilot signal selection ϋ 210 divides the pilot signal into a variable pilot set and a fixed pilot set according to the position of the (four) orthogonal frequency division complex frequency signal and the discrimination result of the antenna, respectively, or performs correlation coefficient calculation, or guides The frequency signal is regarded as a VTU08-0002/ 0608A-A41642-TW/Final 201001964. The correlation coefficient is calculated as a whole. In the case of a plurality of transmitting antennas, the pilot signal selector 21 划 divides the guide signal corresponding to the same transmitting antenna into one pilot set. The initial value calculator 220 receives the pilot # number from the pilot signal selector 21A and is connected to the pilot signal evaluation module 23, and the initial value calculator provides channel estimation for the pilot signal evaluation module 230. The initial value. In one embodiment 'the initial value is wrong! Objects cannot be created with the edit function variable code. Where Y is the received pilot signal and X is the known transmitted pilot signal. " The pilot signal evaluation module 23 进行 performs time domain and frequency domain on the pilot signal according to the division result of the pilot set generated by the pilot signal selector 21 以及 and the initial value of the channel estimation generated by the initial value calculator 220 The correlation coefficient is calculated on the estimate. Its calculation formula is: — ~ k')Trmx Af) .................................... 1) rt{f- V) = ····;···..-------------(2) where the error! The object cannot be created with the edit function variable code. Objects cannot be created with the edit function variable code. The pilot signals in the frequency domain and the time domain direction respectively, the error object cannot be created with the edit function variable. For the maximum delay spread, the error object cannot be edited. Variable code to establish. For maximum Doppler shift, error! Object cannot be created with the edit function variable code. For Orthogonal Frequency Division Multiplexing (Spacing) 'Error! Object cannot be created with the edit function variable code. The symbol length is orthogonally frequency division multiplexed. The channel estimation information calculator 24〇 is connected to the pilot signal evaluation module VTU08-0002/ 0608A-A41642-TW/Final 201001964 230' according to the pilot letter W = R (R+ cover 1) The filter coefficient obtained by the estimation module 230 is calculated by generating channel estimation information, wherein β is a coefficient related to the modulation mode, and the error! Created with the edit function variable code. 'SNR is the pilot signal-to-noise ratio, I is the unit matrix, R is the correlation coefficient matrix, error! The object cannot be created with the edit function variable code. That is, R is affected by the time domain and the frequency domain. The effect of dimension variables. The following will use the microwave access global interoperable access system's Fully Sub-Channel (FUSC), Partially Usable Shared Channels (PUSC) and Space Time Codes. The present invention is further described in part by using a working mode such as sub-channel mode (STC PUSC) in conjunction with a specific example. Fully using the sub-channel mode in the fully used sub-channel mode of the microwave access global interworking access, the sub-carriers included in each sub-channel Diffusion is spread over the entire frequency band, and all the sub-channels can be used by the transmitter to obtain the maximum frequency diversity. The full-subchannel mode of the downlink calls all sub-channels, first the pilot sub-carriers are specified in the available sub-carriers, and then the remaining The following subcarriers are divided into subchannels. The pilot signal can be divided into two variables. The frequency set VariableSet#0, VariableSet#l, and the fixed pilot set ConstantSet#0, ConstantSet#l' indicate the number and position of the pilot set in the fully used subchannel mode. Table 1 1024 subcarriers , the downlink uses the subchannel mode pilot position completely __ pilot signal value annotation VTU08-0002/ 0608A-A41642-TW/Final 12 201001964

VariableSet#0 36 0, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264, 288, 312, 336, 360, 384, 408, 432, 456, 480, 504, 528, 552, 576, 600, 624, 648, 672, 696, 720, 744, 768, 792, 816, 840 ConstantSet#0 6 72*(2*n+k)+9; where k=0, n=0~ 5. When the pilot subcarrier index is calculated by the above formula, it may include DC subcarriers VariableSet#l 35 0, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264, 288, 312, 336, 360, 384, 408, 432, 456, 480, 504, 528, 552, 576, 600, 624, 648, 672, 696, 720, 744, 768, 792, 816, 840 ConstantSet#l 5 72 *(2*n+k)+9; where k=l, n=0~4, when the pilot subcarrier index is calculated by the above formula, it can contain DC subcarriers to see, the position of the —jtb pilot The constant set of pilots remains unchanged, while the positions of other pilots satisfy the following formula'. The pilot set can be changed: 雠 办 办 代 51 51^®^ 〇 According to the pilot signal in Table 1, it can be based on the error! Objects cannot be created with the edit function variable code. An initial estimate of the variable position pilot signal and the fixed position pilot signal is obtained. Where γ is the received pilot signal and X is the known transmitted pilot signal. Figure 3A shows the single-shot single-receipt VTU08-0002/ 0608A-A41642-TW/Final 13 201001964 in the microwave access global intercommunication receiving system. The antenna uses the sub-channel mode and the variable position guide f in the sub-channel mode. intention. It can be seen that in the variable position pilot set, every two phase = pilot position is separated by 6 subcarriers and the same symbol is separated by 12 subcarriers. That is, in Fig. 3A, the even-numbered symbols and the odd-numbered 帛 minimum interval are 6, and the even-numbered symbols and the odd-numbered symbols in the odd-numbered symbols are separated by 12. In other embodiments, the pilot spacing may also be other numbers. A third figure shows that the fixed position pilot in the fully used subchannel mode can be seen. The pilot bits in the even and odd symbols in the figure are fully used in the global interworking of microwave access (4). First, the system performs a pass-by-turn process instance for the received orthogonal frequency division multiplexing symbols. In step 410, the orthogonal frequency division = data location is divided into a fixed location pilot set and a pilot set. The location of the pilot signal can be seen in the figure and

law. For the division of Si, the method of dividing the storage address, and the division of the frequency (four) may be performed by using the _ splitter pilot characteristic described in 纟1, or may be the step 420 of the present invention. For all of the pilot sets described above, the pilot set and the variable position are difficult to start (4), including the 'LS algorithm' in the fixed position, ie according to the error, • in one embodiment, the generation is established. The pilot signal initial material is obtained, and the pilot signal 'X is a known transmission pilot signal' received by the twirling function. Wherein Υ is connected to VTU08-0002/ 0608A-A41642-TW/Final 14 201001964 It can be understood that initial estimation by dividing the fixed position pilot set and the variable position pilot set is an embodiment of the present invention, in other implementations. In step, step 410 may also be performed in step 410. In step 430, the number of received orthogonal frequency division multiplexing symbols is determined. When only one orthogonal frequency division multiplexing symbol is received, step 440 is performed. Since only one orthogonal frequency division multiplexing symbol is received, no time domain filtering is needed, and for one orthogonal frequency division multiplexing symbol, each pilot interval is 12 subcarriers, and thus is obtained according to formula (1). The Wiener filter coefficient is used to obtain the coefficient information. When it is determined in step 430 that a plurality of consecutive orthogonal frequency division multiplexing symbols are received, step 450 is performed. In step 450, the (four) recording money wave of the time-of-flight is first performed according to the pilot position of the variable pilot set, here a one-dimensional Wiener filter.

In step 452, 'the correlation coefficient in the frequency domain direction is calculated and filtered in the same subcarrier position of the two variable pilot sets, and the pilot (four) adjacent to the pilot of the pilot and the pilot signal itself may be used. A total of three pilots (four)

St: Other numbers of pilot signals may be selected for the associated number of carriers. Here, the pilot signal in the frequency domain direction is selected as a fixed pilot set calculation in step 454 of the present invention. That is, the pilot of each position is subjected to Wiener filtering in the time domain direction such as β 疋 pilot. In step 456, the potent ί = Ϊ result is obtained using a linear interpolation function. Since the linear interpolation can be used in the present embodiment, the "channel estimation" can be further improved, and the (four) solution can be continued in the embodiment of = VTU08-0002/〇608A-A41642-TW/Final 15 201001964. The Wiener filtering in the frequency domain direction obtains the estimation result. At the same time, those skilled in the art can understand that it is also within the scope of the present invention to perform the estimation of the frequency domain direction in the time domain direction, and the above steps are for the sake of explanation. 460, the channel estimation information W is obtained according to the result of step 440 or step 456, wherein a combination of correlation coefficients corresponding to different pilot sets is a correlation coefficient of all pilot signals, and channel estimation is obtained by using correlation coefficients of all pilot signals. The information W is obtained to obtain the correct transmission signal. The calculation of the channel estimation information W is described in the channel estimation information calculator 240 in Fig. 2. Fig. 5 shows that 8 consecutive positives are received in the fully used subchannel mode. Inter-frequency division multiplexing symbol, using quadrature phase shift keying coding mode, 1/4 coding rate, moving speed 3km/h, common linear filtering and improved dimension Filtering and performance simulation of channel estimation under ideal conditions, where the horizontal axis is the signal-to-noise ratio, the unit is dB, and the vertical axis is the frame error rate. It can be seen that the computational overhead is greatly reduced and the computation time is reduced. In the case, the improved Wiener filtering method still obtains better estimation results. Part of the single antenna uses the subchannel mode. In the partial subchannel mode, the transmitting end uses a part of the subchannel, which enables partial frequency reuse. Another embodiment of the present invention is an application example when the orthogonal frequency division multiplexing system operates in a partial use subchannel mode. In the partial use subchannel mode, the subcarriers are divided into a plurality of interlaced clusters, each The group contains 14 adjacent subcarriers. Partially using the subchannel mode can apply VTU08-0002/ 0608A-A41642-TW/Final 16 201001964 in the case of multiple magnetic regions, but limits each magnetic region in one cell. The number of groups. In this embodiment of the invention, each block includes a plurality of orthogonal frequency division multiplexing symbols in a time domain, and Each 14 subcarriers are divided into one group in the frequency domain direction. Since each group has a limited length in the frequency domain direction, the improvement in the frequency domain direction is limited, and only an improved calculation in the time domain direction is required. In the frequency domain direction, the linear interpolation function is still used to estimate other subcarriers, so the complexity of the operation can be greatly reduced at the expense of less performance f. Figure 6 shows the subchannel mode in the single-shot single-receiving antenna part. Schematic diagram of the pilot position of a group. It can be seen that there is no need to divide the variable pilot set and the fixed pilot set in the partial use subchannel mode. Fig. 7 is an example of a method flow of the present invention in the partial use subchannel mode. Step 710 is similar to the function performed in step 420 in the sub-channel mode, and will not be described herein. In step 720, a correlation coefficient calculation for the time domain direction is performed for each cluster. In step 730, since the adjacent pilot interval is 4 subcarriers in this embodiment, it is considered that the linear interpolation function can satisfy the accuracy requirement in the frequency domain direction. In this case, the Wiener filtering formula can be reduced to an error! Objects cannot be created with the edit function variable code. . Of course, in other embodiments, the pilot interval may also be other numbers, and when the pilot interval is small and the pilot interval cannot be performed, the correlation coefficient estimation in the frequency domain direction may also be continued. In step 740, the channel estimation information is obtained according to the correlation coefficient, and the channel estimation information is similar to that in the fully used subchannel mode described in FIG. 3, and details are not described herein. VTU08-0002/ 0608A-A41642-TW/Final 17 201001964

Figure 8 shows the use of quadrature phase-shift keying coding mode, 1/4 coding rate, and moving speed of 3km/h when partially receiving sub-channel mode. The performance simulation of ordinary two-dimensional Wiener chopping and improved Wiener filtering and channel estimation under ideal conditions' where the horizontal axis is the signal-to-noise ratio in dB and the vertical axis is the frame error rate. It can be seen that the improved Wiener filtering scheme still obtains a good estimation result under the condition that the computational overhead is greatly reduced and the computation time is reduced. The sub-channel mode is used for the part that uses space-time coding. In the sub-channel mode where the space-time coding is used, the antenna array 4 is a multi-shot antenna. The input information is first divided into k symbols _ and [C1, C2, ... Ck]. After space-time block coding, multiple antennas simultaneously transmit k symbols in two symbol periods. In the first cycle 'antenna burst cl, antenna 2 sends c2... antenna k sends ck; in the second cycle, antenna 丨 antenna 2 sends c 1 *... antenna k sends ck*, on The mark * indicates that the north wheel is taken, and it is often considered that the condition of the channel in the time direction does not change in one cycle.

In one embodiment, two antennas are used for data reception, and this antenna array arrangement is used to illustrate the technical features of the present invention. Sections 9 and 9B illustrate the positions of the equal-frequency signals in the orthogonal frequency division multiplexing symbols received by the receiving system using the space-time coded partial subchannel mode. In Figures 9A and 9B, two eight pilots 901 '902 from different receive antennas are received at each location. The pilot is independent of antenna 0, pilot 902 is from antenna 1, and the period of pilot change is 4^. Therefore, in the sub-channel mode in which the space-time coded portion is used, &lt; , T, from VTU08-0002/ 0608A-A41642-TW/Final 18 201001964, the pilot interval of the same antenna is large, and 2-bit Wiener filtering is used. It is necessary to operate on the positive_divided (four) number of f. Figure (7) illustrates an embodiment of the present invention. In step 910, the antenna receiving module 110 in FIG. 1 determines the receiving antenna condition, including the number of transmitting/receiving antennas, data allocation rules, and the like. In this embodiment, two transmitting antennas are used, so the single antenna determining information is no. In step 920, the transmission data corresponding to the antenna is extracted. In step 930, the correlation coefficient W1 is simultaneously obtained by using a two-dimensional filtering method on the pilot signal of one of the antennas. Of course, in other embodiments, the correlation coefficient may be obtained by using the methods described in FIG. 4 and FIG. . The correlation coefficient W2 calculation of the other antenna is performed in step 940. Step 930 and step 940 may also be performed at the same time in step 950. According to the obtained correlation coefficient WBu, the channel estimation information is obtained by using the two-dimensional wave method. The first diagram shows that in the sub-channel mode where the space-time coding is used, the field receives 8 consecutive orthogonal frequency division multiplexing symbols, and uses quadrature phase shift keying to control the flat horse mode 1/4 brewing rate, moving At a speed of 3km/h, the ordinary two-dimensional dimension 'm and the improved Wiener it wave and the performance simulation of the channel estimation under ideal conditions' where the horizontal axis is the signal-to-noise ratio, the unit is dB, and the vertical axis is error, 1 ° It can be seen that the improved Wiener filtering scheme still obtains a good estimation result in the case of greatly reducing the computational overhead and reducing the computational time. </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> <RTIgt; And the retouching, VTU08-0002/ 0608A-A41642-TW/Final 19 201001964 'The scope of the invention is therefore defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating an example of a microwave access global intercommunication receiving system according to an embodiment of the present invention; FIG. 2 is a block diagram according to a block diagram An embodiment of the present invention, (an example of a channel estimation module in the microwave access global intercommunication receiving system of the present invention is illustrated; FIG. 3A is a schematic diagram illustrating the present invention according to an embodiment of the present invention; An example of a variable position pilot signal in a subchannel mode is fully used in the microwave access global interworking receiving system; FIG. 3B is a block diagram illustrating the microwave according to the present invention according to an embodiment of the present invention. Example for accessing a fixed-position pilot signal in a sub-channel mode in a global interworking receiving system; FIG. 4 is a flowchart illustrating an example of a channel estimation method according to the present invention according to an embodiment of the present invention; 5 is a schematic diagram illustrating a channel estimation method and a conventional channel estimation according to an embodiment of the present invention. Example of a performance comparison of the method; FIG. 6 is a schematic diagram illustrating an example of a pilot signal position partially using a subchannel mode in the microwave access global interworking receiving system according to an embodiment of the present invention; 7 is a flow chart illustrating an example of the channel estimation method flow of the present invention in accordance with an embodiment of the present invention, VTU 08-0002/0608A-A41642-TW/Final 20 201001964; FIG. 8 is a schematic diagram based on An embodiment of the present invention describes an example of performance comparison between the channel estimation method and the conventional channel estimation method according to the present invention; FIG. 9 is a schematic diagram illustrating the present invention according to an embodiment of the present invention. Example of a pilot signal position using a sub-channel mode in a portion of a microwave access global interworking receiving system using space time coding; FIG. 10 is a flow chart illustrating the microwave according to the present invention, in accordance with an embodiment of the present invention An example of a channel estimation method flow using a sub-channel mode in a portion of a global interworking receiving system that uses space-time coding; And FIG. 11 is a schematic diagram illustrating an example of performance comparison between the channel estimation method and the conventional channel estimation method according to the present invention according to an embodiment of the present invention. [Main Component Symbol Description] 100: Worldwide Interoperability for Microwave Access Access receiving system; 110: antenna receiving module; 120: orthogonal frequency division multiplexing demodulation module; 130: channel estimation module; 140: data back-end processing module; 210: pilot signal selector; : initial value calculator; 230: pilot signal evaluation module; 240: channel estimation information calculator; VTU08-0002/ 0608A-A41642-TW/Final 21 201001964 410~460, 710~740, 910~950: steps ; 901, 902: Pilot.

VTU08-0002/ 0608A-A41642-TW/Final 22

Claims (1)

201001964 *, X. Patent application scope: 1 · A method for channel estimation in an orthogonal frequency division multiplexing system, a method for receiving multiple orthogonal frequency division multiplexing symbols, and generating two methods, the method comprising: generating channel estimation information And taking a plurality of pilots in the plurality of orthogonal frequency division multiplexing symbols, and taking a plurality of pilots in the plurality of pilot signals, wherein each pilot signal f in the first pilot set is two:== The number of the first-direction is estimated to be the first coefficient of the production, and the first pilot is concentrated. Performing a second evaluation coefficient calculation in the second direction, a first, a coefficient, based on the first-valued coefficient and a first estimated frequency signal estimation result; and a 4-valued coefficient, obtaining a guide according to the pilot The money valuation results obtained the channel estimation information. For the Orthogonal Frequency Division Multiplexing (OFDM) system, the finite number of pilot signals into the pilot set are used in the Orthogonal Frequency Division Multiplexing (CFD) coefficients. The == method, wherein the first-valued coefficient and the second estimate result are estimates of the pilot signal. The channel for controlling the channel is used in the Orthogonal Frequency Division Multiplexing system, and the method 'where the plurality of pilot signals are divided into the first-A4l642-TW/Final VTU〇8-〇〇〇 2/〇6〇8a 23 201001964 A pilot set when the Orthogonal Frequency Division Multiplexing system works in the microwave access global interworking access system part of the subchannel mode. r 5· The method for estimating a medium channel according to claim 1, wherein the plurality of pilot signals in the plurality of pilot signals are the second pilot set. a second relative position between each of the pilot signals in the second pilot set. The first relative position is different from the pilot signal in the second relative bit/first pilot set. The third evaluation coefficient is calculated to obtain the third evaluation coefficient, and the second and fourth evaluation coefficients are calculated for the derivative number in the second pilot set, and the fourth estimation system = and = a evaluation coefficient is obtained. The second evaluation coefficient, the third pilot ', and the fourth pilot coefficients are the result of the pilot signal estimation. . The method for Orthogonal Frequency Division Multiplexing Coefficients 2 described in Item 5 of Tongzhong 6 Tongqing Patent Range, wherein the first valuation coefficient, the second estimated frequency signal, and the fourth The combination of the pilot coefficients is a method for the guidewire to be used for the orthogonal frequency division multiplexing system and the channel estimation according to item 5 of the patent application scope, wherein the pilot is called eight: The second ^ 7 county 'is the complete sub-channel mode for the brother-pilot ball intercommunication system. The signal used in the Orthogonal Frequency Division Multiplexing (OFDM) signal is the second pilot set: it is a plurality of pilots in the set, and the first relative position of all the r first parties is different. The pilot signal in the direction of the second relative position is subjected to a third evaluation coefficient calculation of '-_2/0608AA4i642m 24 201001964, and the result of the third evaluation is calculated for the coefficient leaf. Calculating a time value coefficient, wherein the fourth coefficient of variation is a linear interpolation operation, the first coefficient, the second derivative total number, the estimated frequency signal value=number, and the fourth pilot The collection of coefficients is the derivative system: the two or two items are used for orthogonal frequency division complex frequency division multiplexing, wherein the evaluation is calculated according to the evening subcarriers in the orthogonal f 1() ^ Wiener chopping with the pilot signal. In the system, the channel ===...the Orthogonal Frequency Division Multiplexing obtains the estimated information of the channel to satisfy the wna + ΚΓ1 shell 1 "the tiger valuation, the fruit obtained the ancient ten capital, ρ * ' where w is the channel estimate R is the estimated result of the pilot signal, 〖constant. System 1 2 = patent range 1 item for orthogonal frequency division multiplexing initial estimation 'two 2 method' which includes calculating the pilot signal a plurality of proportional, the estimated value of the disc is inversely proportional to the received pilot signal to /, the known transmitted pilot signal. The device 5 = the channel estimation in the orthogonal frequency division multiplexing system, the The apparatus includes an inter-frequency division multiplexing symbol, and generates channel estimation information, where 'for each of the pilot signal sets in the first pilot set based on the plurality of orthogonal frequency division multiplexing symbols' Connected to the pilot signal selector, using vna_2/0 Shoubu 642 τ Na (4) 25 201001964 = pilot signal in the frequency band for the first estimate of the first direction Ϊ = second estimate of the second direction Value coefficient calculation, yield 3 = 3 =:;:: coefficient and the second valuation coefficient, obtained: Ji, connected to the guide with a calculator The signal estimation module obtains the channel estimation information according to the estimation result of the pilot signal. The system 1 is used for the orthogonal frequency division multiplexing method according to the 12th patent range, wherein the guide The 'guided ship value= performed by the frequency signal estimation module is calculated as all the first-squareth-derivatives# in the first-pilot set, and the number is calculated as the number in the calculation A finite number of pilot signals in the second direction are performed in the evaluation system 1 in accordance with the fourth embodiment of the OFDM apparatus as described in claim 12, wherein the pilot signal is estimated The combination of the number generated by the module and the second evaluation coefficient is the pilot signal estimate. The apparatus for orthogonal frequency channel estimation according to the fourth aspect of the patent application, when the pilot signal selector When a plurality of first pilot sets are introduced, the Orthogonal Frequency Division Multiplexing system operates in a sub-channel interworking access system using a sub-channel mode. Pi/中6, Λ Λ Patent Application No. 12 The apparatus for orthogonal frequency division multiplexing estimation 'takes a plurality of the plurality of pilot signals into a second pilot set Wherein the pilot signal ντυ08.0002/060δΑ.Α41642TMώα1 26 201001964 is the second relative position in the second pilot set, and the relative position of the diagnosis phase is different from the second relative behavior. The value module pairs the pilot signal in the second pilot set into two;::: the third evaluation coefficient is calculated to obtain the third evaluation coefficient, the number calculation, and the pilot signal in the medium: 3\ performs the second The fourth estimate of the direction is the fourth estimate factor. ^ t ^t6 ;fl 'Al\^ ^ ^ value 俜, the first estimate coefficient in the lean, the second estimate: the octave coefficient and the fourth pilot coefficient are the 8th pass in the system 1 If the orthogonal frequency division multiplexing is divided into the first pilot set and the second pilot set as described in Item 16 of the method, the orthogonal frequency=channel mode is used for global access access of the microwave access. The system fully uses the sub-channel 1 in the sub-system 1 as described in the patent scope, item 16 for the orthogonal frequency division multiplexing signal is a second guide between the plurality of pilot signals in the pilot signals Each of the pilot signal positions in the frequency set is different from all the first relative positions of the second relative field, and the pilot signals of the first direction are calculated according to the first estimate and the third estimate; The pilot signal in the ten direction enters: the coefficient, the 4 operation 'the first estimated coefficient, the second estimated frequency 2: the coefficient, and the fourth pilot coefficient are the combination of the guide ^ 8 8 2 / 0608A-A41642-TW/Final 27 201001964 VIII, 2 〇 · The channel used in the Orthogonal Frequency Division system as described in claim 13 or 19. Meter means, which calculates the estimate for the towel Wiener off wave based on the plurality of orthogonal frequency division multiplexed sub guide New pilot signal symbols. ~ /21 The device for channel estimation in the orthogonal frequency division multiplexing system according to item 12 of the claim patent scope, the towel is obtained according to the pilot money estimation result = channel estimation information is provided w = R ( R+Krl, whose towel w is the channel estimate = Bellow, R is the pilot signal estimation result, and κ is a constant. 22 receiving devices for the orthogonal frequency division multiplexing system, the device includes: a receiving The signal front-end processing module is configured to receive the data by orthogonal frequency division multiplexing symbols; 'Xi, Han, and = channel estimation|set; receive multiple orthogonal frequency division multiplexing symbols to generate channel estimation information; and Receiving the signal back-end processing amount, and performing data decoding according to the channel estimation and the plurality of orthogonal frequency division multiplexing symbols. 23· The receiving device for the orthogonal frequency system as described in claim 22 Wherein the channel estimate I further comprises a pilot signal for taking a complex number of the plurality of pilot signals according to a plurality of pilot signal positions of the plurality of orthogonal frequencies: t is The first pilot set, wherein the first pilot bit is the first relative bit The mother pilot-pilot signal is estimated, and the connection_pilot money chooses to cry in the first direction of the pilot signal in the first pilot set. VTU08-0002/ 0608A-A41642-TW /Final 28 201001964 Coefficient calculation, generating a first estimate coefficient, performing a second estimate coefficient calculation in the second direction on the pilot signal in the first pilot set, generating a second estimate coefficient, according to the first estimate a coefficient and the second estimated coefficient to obtain a pilot signal estimation result; and a channel estimation information calculator connected to the pilot signal estimation module, configured to obtain the channel estimation according to the pilot signal estimation result Information. f ί. VTU08-0002/ 0608A-A41642-TW/Final 29