TW200412092A - Channel estimation in orthogonal frequency-division multiplexing (OFDM) systems - Google Patents

Abstract

A system and method for estimating channel characteristics in orthogonal frequency-division multiplexing (OFDM) systems with transmitter diversity is presented. The disclosed approach is compatible with the Institute of Electrical and Electronics Engineers (IEEE) "Wireless Local Area Network (LAN) Medium Access Control (MAC) and Physical Layer (PHY) Specification." In the disclosed system and method, an additional training symbol is transmitted during the data period. This provides additional information that may be used to more accurately estimate channel characteristics.

Description

200412092 发明 Description of the invention: [Technical field to which the invention belongs] The present invention provides a general system and method, and particularly relates to a system and method for estimating channel characteristic values, which are applied to orthogonal frequency division using a transmission diversity architecture. Multiplexed system. [Previous technology] Radio-frequency local area network system operation is strictly controlled by the US federal agencies. For example, the use of 5.15-5. 25 GHz, 5. 25_5ί 35 GHz, and 5.725-5.825 GHz unlicensed national information structure (u-nh) is subject to US Federal Regulations (CFR) 15.407 Section 47 specifications. Not only does the US Federal Regulations regulate the use of radio frequency networks, other organizations, such as the Institute of Electrical and Electronics Engineers (IEEE) also regulate the technical specifications of wireless networks. This ensures interoperability of wireless systems from different manufacturers. For example, "Wireless LAN Network Access Control Layer and Physical Layer Specification: High-Speed Physical Layer in 5Ghz Band" (wireless lAN Medium Access)

Control (MAC) and Physical Layer (PHY) Specifications * High-Speed Physical Layer in the 5 GHz Band, hereinafter referred to as the IEEE 5Ghz 6 200412092 standard, establishes some specifications for systems operating in the 5Ghz band. In the IEEE 5Ghz standard, a part of it is about a physical layer convergence procedure (PLCP) sublayer of an orthogonal frequency division multiplexing (OFDM). Figure A shows the frame format of a Presentation Protocol Data Unit (PPDU), one of the IEEE 5Ghz standards. As shown in the first figure A, the display cooperation: the frame of the shell material unit includes: a short training period (sh〇rt_training peri〇 (j) H〇; a long training period (long-training period) 120, then After the short training period ho, a signal period (signaling period) 13Q, followed by the long training period 120 ′ and multiple data periods 140, 142, and 144, followed by the letter 5 After period 130. According to the IEEE 5Ghz standard, the long training period 120, signal period 130, and multiple data periods 14, 40, 142, and 144 all include a guard interval (GI). The short training period 110 includes ten A symbol (Ji 6 · ·. A, "), whose function is " ί slogan 4 huan '(signal detection), preliminary frequency acquisition (coarse—freqUenCy

acquisition), diversity reception selection (diversity seiection), and other features of the IEEE 5Ghz private standard. About short training periods Η. The full specification of is defined in detail in the IEEE 5Ghz standard and will not be discussed in more detail here.

The long training period 120 includes a guard interval ⑽) and two long training symbols (7J and redundant). According to the iEEE 5Ghz standard, each long-cut symbol consists of 53 subcarrier symbols. Its DC voltage value is zero, and its content is generated by the _ string of digital sequences I after operation. The number sequence j is as follows: Z = {U, -1, -U, l,-[Eq. 13. In addition, the 臓 5Ghz standard defines the operation function for generating long training symbols as: 53 χ (ί) = w { t Λ xijz ^^^ ~ ^) ^ F {t ~ TGI2) ㈣, [Eq. 2], where Chan is the long training symbol—time_symbol; heart) is a weighting factor, the function of which is the signal Spectral inspection (speca-ing); 々 is-the subcarrier argument; double 々) is one of the training symbols defined by Eq. 1 to "'but the guard interval, which is the value in the IEEE 5Ghz standard Is l 6 s. The IEEE 5Ghz standard not only defines the internals of the long training (in accordance with Eq. 2), but also specifies the number of long training symbols to be two (yj times-, "magic 'to increase the accuracy of channel estimation 0 and' IEEE 5Ghz The standard stipulates that the content of the first long training symbol is the same. Therefore, the same long training symbol ^ Z and the second long training symbol Z are designed. The first long training symbol J 155 and the > H 65 is sequentially transmitted at a long training period of 120. Therefore, the diversity orthogonal transmission of one or two transmissions is as follows: industrial system (as shown in the second figure), ~ the first transmitter 260 ( 1) During the long training period 165a on a first channel; within the time period, send the two long training symbols / 155a and / S 170a within the first pass (2) within the time period of 30th & , The transmission of data and data; and, the transmission data / ¾ 180a and ⑶ in the subsequent data period called 142 / ¾ 190a on the first channel. Similarly, a second transmitter 265 transmits the following content ... · During the time period of long t) i |, the second long view symbol ^ na and ^ 165b are transmitted on a second pass. (1) within the signal period 130, transmit the signal information snob from the second channel; and, (3) within the subsequent data periods 140 and 142, transmit the data Λ 180b and the public 190b to the second channel Channel total. A receiver 205 receives transmission signals from the first and second transmitters, and the reception signal is a function of transmitting a payment element and a channel charaCteriStiC. It is better to remove the time-lapse series, and do it every time the symbol is received—the reverse-side sequence conversion operation. 200412092 So, for a two-branch transmission diversity orthogonal frequency division multiplexing system as shown in the second figure, the received signal K on the frequency axis can be expressed as: ： ^ (Η ^ ×) + (ΗΒ · χ) + Zη '[Eq. 3]. Where Z is the received noise, and you are the channel characteristic value on the frequency axis, and it is assumed to remain unchanged within the frame duration, and the transmission delay of the two channels is also The assumption is the same. Because the same long training symbol / transmission is on the two transmitters of the two transmission diversity systems, Eq. 3 can be simplified as: y ^ {ha ^ hb) -x ^ z ,. [Eq. 4]. Similarly , The subsequent received data blocks can be expressed as: y2 = (ha + hb) ^ x + z2j [Eq · 5], Y3 = {Ha + Hb) ^ S + Z3, [Eq. 6], Y4 = HA.DAl + HB.DB, Z4, [Eq. 7], and y5 = ha.da1 + hb.dB2 + z5 [Eq. 8]. Combining Eqs. 4 and 5 gives the following equation: (Y ^ Y2) -r = (ΗΑ + ΗΒ) \ 2 \ χ \ 2) ^ (ζ ^ ζ2) · χ \ [Eq. 9], after shifting the term, it can be rewritten as ... 10 200412092 A + 圮 (z 丨 + ζ2) · χ 2 ~ 2, or more precisely: HA (k) + HR (k) = ^ hm)) · X {k) (Z {(k) H-Z2 (k)). X (k) 2 2 , Moxibustion = 1, L, ", [Eq · l0], where 丨 is the number of subcarriers of the orthogonal frequency division multiplexing system, and 々 is the argument of the subcarrier. In Eq · 1, for all 々 values, x (々) e {± 1}, so the complex number it / ⑷ of the round symbol / α) is also the same as the transmission symbol. In addition, because the male) e {± 1}, the square term of the transmission symbol / U) 丨 / ⑷ | 2 will be Bu. Furthermore, because z (/ :) e㈣, (Z⑷ + Mod U)) / U) and The statistical value of (/ (々) + Mod (值)) is generally the same. Ignoring the noise term, the integrated eigenvalues d of the two channels (from + you) can be estimated by the following equation: k = hLjN [Eq. 11], although Eq · 11 provides a method for calculating the integrated channel eigenvalues from Obviously, repeated transmission of symbols / can't help distinguish the channel characteristic values of individual channels (total you). In other words, because a single symbol / is transmitted on the two transmission channels (forbearance and you), the channel characteristic value of the system can be expressed by a single binary equation, and only the comprehensive channel characteristic value extension can be calculated. . In addition, although repeated transmission of symbol j can increase signal noise 11 200412092 ratio (shoho-noise ratl0, SNR), but the improvement of signal noise ratio does not help calculate the characteristic value of individual channels. Although there are some complex algorithms that can separate the special & value of individual k from the integrated channel special added value, all the surface algorithms need to make additional assumptions on the channel miscellaneous before they can be correctly estimated. Eigenvalues of each job. Therefore, these channel estimation algorithms are only suitable for these hypothetical conditions. Also, because of the high computational complexity of these channel side-effect algorithms—when the branch transmission diversity system is expanded to more branches (such as three or four branches), the computational complexity will grow exponentially. . Therefore, there is a need in the industrial field for which there is no solution to solve the above problems, so as to make up for the shortcomings and inadequacy of existing algorithms. [Summary of the Invention] The present invention is a system and method for estimating channel characteristic values, and is applied to the environment of a positive-parent frequency-division multiplexing system using a transmission diversity method. In short, 'an embodiment of the system of the present invention includes a transmission unit in the architecture, and the function ^ paragraph transmission-training symbol threat + channel, at the same time, the training symbol channel is transmitted; the training is transmitted in the second period The number of symbols—a total number of symbols in the second channel, and a negative number in the training symbol—a total number of symbols in the second channel. Mo Yue mentioned that the channel characteristic value estimation method is based on the transmission diversity architecture 12 200412092 orthogonal frequency division multiplexing system environment. The operation steps of an embodiment of the method of the present invention include: transmitting a training symbol on a first channel in a first period; transmitting the training symbol on a second channel; and transmitting the training symbol in a second period. Among them, a plurality of complex symbols are transmitted on the first channel; at the same time, a negative complex conjugate symbol of one of the training symbols is transmitted on the second channel. After reviewing the illustrations and implementations below, the artist should be able to easily understand other systems, methods, functions, and advantages of the present invention. Moreover, all such systems, methods, functions and advantages are within the patent scope of the present invention. [Embodiment] The embodiment shown in the drawings will be described in detail below. Although some of the embodiments have been shown in the above figure, the embodiments of the present invention are not limited to this. On the contrary, the scope of the present invention covers other related, partially modified or equivalent embodiments. w Some embodiments of the invention will be described below. In these embodiments, extra training symbols are transmitted to achieve the purpose of accurately estimating channel characteristic values. Different from previous systems and methods that must consume huge computing power or have additional operating assumptions for a multi-transmission diversity system, the embodiments of the present invention only require simple computing power and make fewer operating assumptions for multi-transmission diversity systems. . The second graph A and the third beta graph illustrate an embodiment of a system for estimating the channel characteristic 13 200412092 value. The third diagram A shows the symbols transmitted by a first transmitter, and the third diagram B shows the symbols transmitted by a second transmitter. Figures 3A and 3b show a physical layer convergence procedure (PLCP) preamble field, which is an embodiment of the present invention, and its function is signal synchronization. As shown in Figures 3A and 3B, the header field of the entity layer convergence program contains: a short training period of 31; a long training period of 320, which follows the short training period of 31; a signal period , After the long training period 320; and a plurality of data periods 34, 342, 3, etc., after the signal period. According to 臓 5Ghz, the program segment 31, long training period 320, signal period 330, and multi-data period 34, 342, 344 all include a protection time interval.丨 Xida pays attention to the short training

310 'according to the 5Ghz standard. After the short training symbol is transmitted, the long training symbols u and / 365a are transmitted in the long training period 32 (). Here, capital ^ represents-what is the meaning of the group frequency axis of the orthogonal frequency division system is a vector (gift, including ㈣ prime unit t), where ㈣ is the number of children of the orthogonal frequency division system . The symbol ^ element JU) is transmitted by the first child button. It must be known that, before launching through a line, 'the flight | will pass the inverse Fourier transform. 一. A) The operation' becomes the time axis signal, and add ―Cycle_ 14 200412092 (cycllc preflx) ‖ and then use a The RF module is converted into an RF analog signal. Immediately after the symbol / repeated transmission, the signal data U70a is transmitted in the training period 330. After sending the money data ^, the long complex symbol _ complex number is subtracted. It is sent at -Q-data period 34Q. As mentioned above, because every prime is a real number (™ ber), every element in Ya is also a real number. At the same time, because every element in I is a real number, the island z is the same. However, it must be known that outside the 臓 5Ghz standard, ^ No—it must be a real number, it can be a complex number, and it has imaginary elements. Similarly, as shown in the figure, the second transmitter transmits training symbols 31Q after the short training day according to the dirty test standard. #After the short training symbol is transmitted, the long training symbol / 355b and / 365b are transmitted _ training period immediately after the symbol {repeated transmission, the signal data fiber b is transmitted at the training and training period 33 °. After the signal data is transmitted as b, the long training symbol-negative complex number common symbol_ is transmitted in the first data period 340. As mentioned above, because each element in z is a real number, naturally, every element in -f is also a real number. It is also necessary to know that outside of the dirty standard, / does not have to be limited to real numbers, it can be complex numbers, and has imaginary elements. Based on this knowledge, if / is-plural, the symbols transmitted in the periods 385a and 3c can be (U, H Weilai W-explicit symbol axis. To simplify the description, the following description 200412092 will use symbol pairs) As an example. As described above, the embodiment of the present invention is not only to repeatedly transmit training symbols /, the system of the third graph A and the third graph B adds transmission conjugate symbols / on the first channel, and Send negative conjugate symbol-/. The benefits of adding the teleportation symbols ^ and-/ will be described below and illustrated with the fourth figure. The fourth figure shows a two-transmit diversity orthogonal frequency division multiplexing system including a wireless device 0 (wireless device) 470 and a receiver 405. The wireless device 470 may be an access point unit of a wireless local area network, a wireless local area network card, a cellular electrical activity, a wireless personal digital assistant (PDA), or It is a portable computer with wireless transmission function. As shown in the fourth figure, the wireless device 470 includes two transmitters 460 and 465 for transmitting data in an orthogonal frequency division multiplexing environment. The receiver 405 receives signals transmitted by the two transmitter sides and 465. As shown in the fourth figure, a first channel transfer function always changes the signal transmitted by the __th transmitter side, and the second channel transfer function is the signal transmitted by the second transmitter 465 Cause change. This channel transfer function is the channel characteristic value. Therefore, when the first transmitter 460 and the second transmitter 465 transmit the symbol ^ (the steps are: first perform inverse Fourier transform operation on the symbol to generate a time axis signal !; then add-before the loop Set the tuple to generate gamma; through a radio frequency module, it will be converted into 16 radio frequency ^ ° 'and transmitted using a transmission antenna; ^), the received symbol κ on the frequency axis can be expressed as:, 1 疋Brother Yi receives noise from Fu Yuan. Because the same training symbols / transmissions are used on the second transmitter of the special-set tool set system, the help · 12 can be simplified to:

Disgrace Α) .χ + Zι [Eq. 13].: ,,, because the same training symbols are transmitted again, the second receiver ^ sent by the two transmitters 46 and the place can be expressed as: Y ^ + Hb) .X + Z2 [Eq. 14]. Also, if the signal data 370a is transmitted next, it is a third transmission symbol Γ3, and the received symbol is: ^ ⑼ + [Eq. 15], ', where S is Signal data on the frequency axis. In the embodiment, when the signal data ^ is transmitted, the "common number of training symbols / 3/3" is transmitted on the first transmitter side and becomes the fourth ^ 7; *, the long training symbol The value of the plural number is transmitted at the first-transmission of 465 'to become the fourth symbol $. As mentioned above, because it is a real number, the complex common number element is a negative complex number total element — Λ is the riding number. In addition, for the same reason, there are the following relations between the symbols: 17 200412092 [Eq. 16], -Ϊ--Χ [Eq. 17], and \ X (k) \ 2 = l 〇 [Eq. 18] · Therefore, according to the IEEE 5Ghz standard, the fourth receiving symbol can be expressed as: Y4 = (HA-xy (HBi-X) yz4, [Eq. 19], _ or, further simplified to ·· Υ4 = (ΗΑ -ΗΒ} χ ^ Z4 [Eq · 20] · Combined with Eqs. 13 and 20, a method can be provided to calculate the tolerance and counseling values separately. In other words, unlike the previous technology, only the integrated channel characteristic values (from -Similarly), the present invention can separate and calculate individual values from the following, because: (Υ ^ Υ4) · × * = ({ΗΑ + ΗΒ) · × + ^^^ ((ΗΑ-ΗΒ) · χ + Z4) · Χ * = 2Hx \ X ^ {Z ^ Z, \ r · [Eq. 21]. It must be noted here that each variable item in Eq. 21 is an orthogonal frequency division multiplexing One of the symbols is the frequency axis signal. If it is described from the angle of the subcarrier, Eq. 21 can be rewritten as: 18,412〇92 [Eq. 22], where the number of subcarriers in the orthogonal frequency division multiplexing system is at least, And 々 is the argument of the subcarrier. After calculating the difference between Eq · 13 and 20, the channel transfer function is strict.) The following equation can be used (, Ye Bugang + Liao Fu) 2 [Eq. 23] · Also, according to Eq. 23, Ha can be estimated as: Any good Yigang + Liao. Xiong) k = \ ， 1, N [Eq. 24 ], Or, the simplified expression is: HaJY ^ 'x 2 [Eq · 25] · It must be noted here that in Eqs. 24 and 25, an estimation error and noise terms (say magic / / 2 is related. In general, the mean (mean) of the estimation error of this noise term is 0 (j? ((Z 丨 + Z4) x / 2) = 〇, f is a statistical expectation value function). Moreover, The variation of the estimation error is σ〗 / 2 · (var ((Z + Z〇J / 2) = var (U + Z4) / 2) Second Doctor ((ζ! + Ζ4) / 2 Bu σ] / 2, where var (;) 疋 statistical variation value function, and the variation values of Z and% are assumed to be 4). The characteristic value of the first channel can always be calculated in a similar manner: (方式, -Υ ^ -Χ + ~ ^ ηα-Ηβ) · × ^ -Z4) · × * = 2Ηβ · \ × \ 2+ (Z ^ Z4) · × * 19 200412092 [Eq. 26], which is further simplified as:

Ht or [Eq · 27].

[Eq. 28]. Therefore, it can be estimated as: Η., 〇W4) l 2 [Eq. 29].

As with the estimated values of Eqs. 24 and 25, the estimated error of one of E · and 29 is related to the noise term (^ U) 272. Therefore, the average value of the estimation errors of the noise terms is “0 (double UW / 2H))” and the variation of the estimated rank difference is 4/2 (var ((U〇J / 2 > ν8Γ) ((^ Κ4) / 2) = σ] / 2). It can be seen from the derivation of Eqs · 12 S 29% formula that by sending the // — / in the first ^ knife of the data period, each The characteristic values of the individual channels can be accurately calculated. Therefore, the method is not limited to estimating the characteristic values of the integrated channels. The method of the present invention can also be used to estimate the characteristic values of the individual channels. In another embodiment of the present invention, Eqs is combined with 13, 14, and 20, you can get better 20 200412092 signal integrity and lower estimation error. Because Eqs · 13 and 14 are received signals after repeatedly transmitting the same training symbols, combining these two equations can be considered as further Signal averaging. Therefore, by using repeated transmission of training symbols, the benefits of signal-to-noise ratio improvement can be obtained. The individual channel characteristic values can be calculated according to the following equation: W + r2 + 2r4) r = | outside + (Zi + Z2 + 2ζ4) · X * [Eq. 30], and H _ (^ + y2 + 2y4) -x (z, + z, + 2z, Vx " 4 ~ 4 or, equivalently expressed as: [Eq · 31], magic +2 [⑽. 录) hlL ^ 4 [Eq. 32], so it can be estimated from: Bu Ying) ι + 明) + 邛 _ • Male), [Eq. 33] 4? * Moreover, different from the calculation of Eqs · 24, 25, 28, and 29, the estimation error caused by the noise X member in Ecl · 32 is (2 + 2 + 2 / ) // 4. So, the average value of the estimation error is 0 (Han (say 2/4) ^ 74) = 0), and the variation value of the estimation error is 3 $ / 8 21 200412092 (var ((// ^ + Z + 2Z) // 4) = var ((^ I + 石 +2 石) / 4) = 3σ] / 8, which assumes that the variation value of /, stone, and Z is σ). It can be seen from Eq. 32 As a result, the variation of the estimation error is reduced, and the estimation accuracy is improved. Similarly, the characteristic value of the second channel can also be obtained by the following equation: [Eq. 34], In the above formula, the average of the estimation error The value is 〇 (Wind (Fen Mo-2Z4) J / 4 > 〇) and the variance of the estimated difference is W / 8 (var ((^ + ^ 2-2 ^) // 4) = var ((Z + Z2-2 ^) / 4) = 34/8, where z, stone, and% are assumed to be variability values.) In general, by transmitting additional long training symbol fires, or complex conjugates of the symbols Symbol / and negative complex conjugate symbol— /, miscalculation The variation value can be further reduced for as much as the above-described transmission diversity system, a further embodiment of the present invention may be one as method 'channel characteristic estimated value. The fifth and sixth figures show embodiments of this method. The fifth figure is a flowchart showing the implementation steps of this method. It operates on one or two transmission diversity orthogonal frequency division multiplexing systems. According to the 臓 5Ghz standard, the signals transmitted in the fifth picture all include the guard time interval. As shown in the fifth figure, during a first period, a training symbol is transmitted on the first and second channels (step ·). In the embodiment, the wireless money 470 includes a first channel transmission unit (transmitQgic) 555 and a second channel 22 200412092 a transmission unit 565 is transmitting information to the first channel and the second channel. Immediately after training symbols are transmitted in the first period (step 52G), in the second period, a total of ... symbols of the symbols are transmitted in the-channel (step ca). At the same time, in the second period, the -negative complex co-reversion of the symbol is transmitted to the second channel (step ⑽). If the channel estimation method is based on the dirty 5Ghz standard, the first period is a long training period

One is the time frame of the header block of the convergence process at the physical layer, and the second period is one of the subsequent data periods. The sixth figure is a flow chart showing a method for estimating channel characteristic values, which is implemented in the receiver 405. As shown in the sixth figure, a receiver receives symbols (step C). When the symbol is received, the individual channel effect can be calculated from the received symbol (step 63). This individual channel effect can be used to estimate the characteristic value of the individual channel (step 640). In the embodiment, the receiver 405 includes a receiving unit 625, an individual channel effect calculation unit 635, and an estimated saponin 645, which are respectively used for receiving in the sixth figure (step 62) and the individual channel effect calculation (step 630). ) And estimation (step 64). Furthermore, in an exemplary embodiment, the receiver 70 is an analog signal such as the transmission signal in the fifth figure. In addition, for a 7-branch diversity branch system, the receiver 405 receives / 7 symbols in step 620, where each symbol is a signal after the same training symbols are transformed by different channel effects to form a / 7 System of 77 simultaneous simultaneous equations. With reference to the equations of Eqs. 12 to 34, this; 7 23 200412092 channel characteristic values can be calculated individually. As can be seen from the fifth chart and the sixth chart, the practicality of this method can obtain more accurate estimates of the individual channel job values, instead of just estimating the combined channel feature values, or the required channel feature values as additional Assumptions. Although the exemplary embodiments of the present invention have been mentioned above, those skilled in the art should understand that the above-mentioned embodiments of the present invention can be changed and modified. For example, for the sake of explanation, the two-transmit diversity system is a secret check, but the artist should understand that the method mentioned above can be extended to multi-transmit diversity systems (three, four, or more). Support wheel> In addition, although the fourth picture is not the antenna of the wireless device 47G, those who are familiar with it should know that the transmitter can be a wireless area secret access point unit,-wireless LAN card,-honeycomb Phone, a wireless personal digital assistant, or other similar wireless device that can send and receive data. Also, although in the embodiment of the present invention-additional training is transmitted to the special section ... This additional training symbol can also be transmitted in any subsequent period of the data period. Also, although the third A and u albums show the additional saki symbol (such as 'the complex number of this long training symbol') Or negative complex numbers total _ yuan), the artist should understand that more additional training symbols can also be applied to this system, by mentioning the signal-to-noise ratio in the * capture channel estimation, and used for calculation Individual channel characteristics of a multi-transmission money system (^^ one transmission) Also, although several embodiments of the present invention follow the EEEE standard, those skilled in the art should understand that the method of the present invention can provide arbitrary orthogonal distributions and sufficient transmission environment. Also, although the fine E 5Ghz The standard is used to describe part of the concept of the present invention. Learners of this art will be savvy. 'Benfa H Seimura also means ffiEE 2 standards (IEEE concept.llg) or other similar wireless standards, regardless of the operating frequency band. All such changes or changes should be within the scope of the patent of the present invention. [Simplified description of the drawings] In order to make the description of this article more pure, the following touches are provided with simple descriptions. Figure-A and Figure- Figure B is a block diagram of the packet message, the message framework of the green agreement standard presentation protocol data unit (P Hall ntation P purchase c〇1 Data _, surface). The second figure is-the architecture diagram 'drawing _ two transmission diversity The orthogonal frequency division multiplexing system operates in accordance with the IEEE 5Ghz standard. Figures 3A and 3B show an embodiment of a system of the present invention for estimating channel characteristic values. The fourth figure is a rack According to the embodiment of the present invention, a channel characteristic value is shown. The measurement system is used for one or two transmission diversity orthogonal frequency division multiplexing systems. The fifth figure is a flowchart showing an embodiment of a method of the present invention, which is applied to one or two transmission diversity positive parent division Age-of-transmission H-end, used to estimate channel characteristic values. 25 200412092 The sixth diagram is a flowchart showing one embodiment of a method of the present invention, which is applied to one or two transmission diversity orthogonal frequency divisions. One of the receivers in the multiplexing system is used to estimate the characteristic value of the channel. [Schematic mark description] 110 Short training period 120 Long training period 130 Signal period 140 Data period 142 Data period 144 Data period 150 First long training symbol Yuan 155 first long training symbol / 160 second long training symbol 165 second long training symbol yf 170 signal data S 180 transmission data Θ 190 transmission data and 155a long training symbol yT 155b long training symbol J 165a long Training symbols / 165b Long training symbols J 170a Signal data Xi 170b Signal data 5 180a Transmission data / ¾ 180b Transmission data Λ 190a Transmission data / ¾ 190b Transmission data and 205 Receiver 260 First transmission 265 second transmitter 26 200412092 310 short training period 320 long training period 330 signal period 340 data period 342 data period 344 data period 355a long training symbol J 355b long training symbol J 365a long training symbol J 365b long training symbol Yuan J 370a signal data 51 370b signal data 385a long training symbol / one complex number of car symbols / 385b long training symbol J one of negative value complex conjugate symbol- / 390a transmission data and 390b transmission data / ¾ 405 Receiver 460 First transmitter 465 Second transmitter 470 Wireless device 555 First channel transmission unit 565 Second channel transmission unit 625 Receiving unit 635 Calculation unit for individual channel effects 645 Estimation unit 27

Claims (1)

zuuHizuyz's patent application scope: • A method for estimating channel characteristic values, a multiplexed wireless communication system, the steps of which include: Application to one or two wheel diversity diversity orthogonal frequency divisions. And the long net On the day, the specifications of & are in line with the "Medium Access Control Layer and Physical Layer Standards of the Wireless Area" formulated by the Institute of Electrical and Electronics Engineers of the United States; Road; — The second channel; during the Behr period, a complex number of the long training symbols is transmitted in the first data period; 'transmit #long training symbols—the negative complex numbers are associated with The first protagonist faces the long training symbol and the plural of the long symbol. There are a total of symbols and / or a car, and a negative complex number. From the pure symbol, the compound character of the trained symbol element _yuan, the negative value of the long spider symbol element «total_element, is calculated to obtain the channel characteristic value. 2 · —The method of estimating the characteristic value of the art path, the steps include: transmitting 1 symbol element in the first period in the first channel; in the first period, such as' axis · fudan—the second channel; 28 200412092 Transmitting a complex conjugate symbol of the training symbol to the first channel in a second period; and transmitting a negative complex symbol of the training symbol to the first channel in the second period; The first channel. 3. The method as described in item 2 of the scope of patent application, wherein the step of transmitting training symbols on the first channel in the first period includes:-Long training in the header block before the entity layer convergence program packet During the period, the training symbol is transmitted to the first channel. 4. The method as described in item 3 of the scope of patent application, further comprising: within the training period of archiving and wealth before the entity's green training sequence packet ', transmitting the training symbol to the first channel again. Exercises> If you apply for a full-time job, the second step is to transfer the training to the second channel in the first period, including the long training period in the first block before the physical layer receives the sequence packet. Within, send the training symbol to the second channel. The method further includes: 6. The method described in item 5 of the scope of patent application, which is slotted before the physical layer convergence program packet, fearing that the long training period in the master block 'retransmits the training symbol in the first Two channels. 29 200412092 7. As described in the method of item 2 of the patent scope, /, T The step of transmitting the plural of the Li Dong Fu Yuan in the second channel during the second period, including: Convergence procedure at a physical layer When a packet of data is contained in the slave, the complex conjugate symbol of the training symbol is transmitted to the first channel. 8. As described in item 2 of the scope of the patent application = The step of transmitting the negative number of the training symbol in the second channel by Youguzhong during the second period, including ... During a time period of one asset, the negative complex conjugate symbol of the training symbol is transmitted to the second channel. 9. The method according to item 2 of the patent application scope, further comprising: transmitting additional training symbols to the first channel during other periods. • The method described in item 9 of Langzhong ° H15, wherein the number of other periods is proportional to the number of transmission channels. 11. The method as described in item 2 of the scope of patent application, further comprising: transmitting training symbols outside the copper channel to the second channel in other Japanese products. 12.-A method for estimating a channel characteristic value, including: receiving a -th-symbol, and the first symbol includes: the mouth 70 is transmitted to a first channel within a first-period, and the training symbol Yuan, transmitted on a second channel within one inch of each minute; 30 200412092 receives a second symbol, one channel of the training symbol, and the second symbol includes: a complex conjugate symbol Yuan, pass in a second period Transmitted to the training symbol—a negative complex number of symbols, the second channel in the first period; and using the received first and second symbols to estimate the channel characteristic value 13. Road The method is characterized in the method described in item 12 of the scope of patent application, wherein the step of estimating the pass value includes: separating the first channel effect from the first symbol and the second symbol by '; and the second channel symbol and the second symbol The second channel effect is separated in the two symbols. 14. The method according to item 13 of the patent application scope, further comprising: estimating the characteristic value of a first channel from the separated first-channel effect; and estimating the second channel effect from the separated, estimating Measure a characteristic value of the second channel. 15 · —A system for estimating channel characteristic values, including: transmitting a training symbol to a first channel during a period of the first period; transmitting the training symbol to a second channel during the period of the first period; A transmission unit of the channel; a transmission unit that transmits a complex conjugate symbol of one of the training symbols to the first channel in the second period; and 31 200412092 _value a complex conjugate symbol at the first in the second During the period, one of the training symbols is transmitted as the channel's pass unit. 16. As described in item 15 of the scope of patent application, wherein the transmission of the plurality of training symbols in the second period to the total number of symbols in the first channel-channel transmission unit includes: transmitting the plurality of training symbols in one During the data period of the physical layer convergence program packet, a total of vehicles are paid to the transfer unit of the first channel. 17. The defect as described in item 15 of the scope of patent application, wherein during the second period, the transmission unit of the channel transmits a negative plural number of the training symbols to the second symbol; including: ： Count / pay lightly to the wheel transfer unit on the second channel. 18. The system described in item 15 of the scope of patent application, further comprising: Γ 时 助 ’Biography Series-No.-E Chuanlun unit. A system for estimating channel characteristic values, including: receive-the-symbol __ yuan, ㈣-symbols include: on the day _ sent to the 卞 channel; and • 丨 practice symbol 'is transmitted in- A second channel; a receiving unit receiving a second symbol ^ ㈣ & 32 200412092 a complex conjugate symbol of one of the transmission symbols transmitted to the first channel within a second period; and one of the transmission symbols A negative complex conjugate symbol is transmitted to the second channel in the second period; and the receiving unit for estimating the characteristic value of the first and second channels is received using the received first symbol and second symbol. . 20. The system according to item 19 of the scope of patent application, wherein the receiving unit for estimating the channel characteristic value comprises: a receiving unit for separating the first channel effect from the first symbol and the second symbol; and A receiving unit of the second channel effect is separated from the first symbol and the second symbol. 21. The system according to item 20 of the scope of patent application, further comprising: a receiving unit for estimating a characteristic value of a first channel from the separated first channel effect; and a separated second channel effect from the separated first channel effect, Receiving unit estimating a second channel characteristic value 0 33