JP6576443B2 - Wireless communication system and receiving apparatus - Google Patents

Description

  The present invention relates to a wireless communication system and a receiving apparatus.

In digital transmission, since communication disconnection occurs when transmission quality deteriorates, it is desirable to avoid deterioration of transmission quality. The bit error rate is an index of transmission quality, and the bit error rate required for each system is different. For example, in a wireless relay transmission device that digitally transmits television broadcast program material called FPU (Field Pickup Unit), if the bit error rate after inner code decoding is 1 × 10 ⁻⁴ or less, It is possible to correct errors up to error-free (for example, see Non-Patent Document 1).
In mobile transmission using this FPU system, the bit error rate fluctuates every moment according to the state of the transmission path. Therefore, it is necessary to grasp how much transmission margin there is for the required bit error rate in order to perform stable transmission.

Conventionally, as a method of calculating a transmission margin, received power measured at the receiving side, received CNR (Carrier to Noise power Ratio), MER (Modulation Error Ratio), etc., computer simulation, The margin is calculated from the previous verification result obtained by actual measurement or the like.
Since the received power and the received CNR that satisfy the required bit error rate change according to the transmission path characteristics and the influence of interference, a table storing the margin for each transmission path is prepared in advance, and the margin is set according to the transmission path. Is desirable but not realistic. Therefore, it is common to set a transmission margin based on a simulation result by a computer simulation with a predetermined transmission path model or an actual measurement value of the transmission path.

In addition, AMC (Adaptive Modulation Coding) is a wireless technology that optimizes the transmission rate of a wireless device by adaptively controlling the modulation method and coding method according to the quality of the transmission path. It is known and used in HSDPA (High Speed Downlink Packet Access) and LTE (Long Term Evolution).
AMC generally selects MCS (Modulation and Coding Set) that maximizes the transmission rate while satisfying the required bit error rate of the system, based on transmission path information obtained by the receiving apparatus. For determining whether or not the required bit error rate of the system is satisfied, the reception CNR or the like is used as an index of the quality of the transmission path. The reception CNR threshold value for selecting the optimum MCS is set based on the bit error rate characteristics in each MCS obtained in advance based on computer simulation, actual measurement values, and the like.

  As a prior art document, for example, in Patent Document 1, when the number of repetitions is limited in the turbo equalization technique, a modulation method and a coding rate that can complete the decoding process of transmission data with the number of repetitions are described. A technique for selecting is disclosed.

JP 2010-87707 A

ARIB STD-B57 2.0, “1.2 GHz / 2.3 GHz band portable OFDM digital wireless transmission system for transmitting TV broadcast program material”, The Japan Radio Industry Association Error control considering terrestrial transmission line characteristics, Annual Conference of the Institute of Image Information and Television Engineers (1998)

For example, in a multiple input multiple output (MIMO) transmission system in which both a transmission device and a reception device transmit using multiple antennas, transmission quality may deteriorate in an environment where the antenna correlation is high, because it becomes difficult to separate and detect received signals. Are known. Therefore, when the transmission margin is set based on the reception power, reception CNR, etc., which are the indicators of the conventional transmission path quality, the bit error rate is high in the above high antenna correlation environment even though there is a transmission margin with a high reception CNR. There arises a problem of deterioration.
In addition, when a reception CNR before erasure correction processing is used in a transmission line in which narrowband interference signals such as amateur radio are mixed, it is erroneously recognized that the reception CNR is sufficient, and an erroneous transmission margin is set. It leads to.
In the above-mentioned environment, for example, a wireless device that transmits the received CNR obtained by the receiving device as feedback information to the transmitting device and controls AMC based on the received CNR, misrecognizes the optimal MCS. Problem arises.
An object of the present invention is to improve a transmission rate by selecting an appropriate modulation method and coding rate even in a high antenna correlation environment or an environment where a narrow band interference signal is mixed.

  A receiving apparatus of the present invention is a receiving apparatus that generates coded bits from an information bit input by error correction coding processing, and receives a modulated signal that is digitally modulated with respect to the coded bits. Demodulating means for calculating a log likelihood ratio for encoded bits of correction encoding; means for calculating an average mutual information amount for log likelihood ratios for encoded bits; average mutual information amount and required bit error rate A means for calculating a transmission margin from a decoding unit input mutual information amount or a demodulating unit output mutual information amount satisfying the above, and an error correction decoding unit corresponding to an error correction coding from a log likelihood ratio with respect to an input coded bit It is characterized by.

  In addition, the receiving apparatus of the present invention generates coded bits by performing error correction coding processing on information bit input, and performs digital modulation on the coded bits rearranged in a predetermined order by an interleaver having interleaving means. A receiving unit that receives the modulated signal, a demodulating unit that calculates a log-likelihood ratio for a coded bit based on the received signal and a priori information, and data rearranged by the interleaver on the transmitting side A deinterleaver unit having a deinterleaver that rearranges the order back to the original order; a mutual information calculation unit and a margin calculation unit arranged in at least one of the preceding stage or the subsequent stage of the deinterleaver unit; When the means is arranged in the preceding stage of the deinterleaver unit, the means is provided for the encoded bit of the demodulator output input to the deinterleaver unit. A logarithm for the encoded bits of the decoding unit input after rearrangement by the deinterleaver unit when the average mutual information is calculated for the log likelihood ratio. A means for calculating an average mutual information amount with respect to the likelihood ratio, and a margin calculating unit that outputs the average mutual information obtained by the average mutual information amount calculation unit and a demodulator output mutual information amount that satisfies a required bit error rate Alternatively, a means for calculating a transmission margin from the mutual information amount input to the decoding unit is provided, and a logarithmic likelihood for a coded bit based on external information is obtained by a decoding process corresponding to error correction coding from a log likelihood ratio for the inputted coded bit. A decoding means for calculating the frequency ratio, an interleaver comprising an interleaving means for rearranging the coded bits of the decoding section output in a predetermined order, and a demodulating section And means for inputting as a priori information, characterized in that it comprises means for calculating a logarithmic likelihood ratio or hard decision result for the information bits obtained by the error correction decoding means.

  The receiving apparatus of the present invention is the above-described receiving apparatus, and includes an interference detection unit and an erasure correction unit arranged at least one of the preceding stage and the subsequent stage of the demodulation unit, and the interference detection unit is arranged at the preceding stage of the demodulation unit. In this case, it has means for detecting an interference component from the received signal, and when it is arranged at the latter stage of the demodulator, it has means for detecting an interference component for the coded bit output from the demodulator, and the erasure correction And means for performing erasure correction processing on the received signal based on the detection result of interference obtained by the interference detecting means for the received signal input to the demodulating section when placed in the preceding stage of the demodulating section. And the log likelihood for the coded bit based on the detection result of the interference obtained by the interference detection means for the log likelihood ratio for the coded bit output from the demodulator. To degree ratio Means for performing a loss correction process, a means for calculating an average mutual information amount with respect to a log likelihood ratio with respect to encoded bits after the erasure correction process, and an average mutual information amount obtained by the average mutual information amount calculation means And means for calculating a transmission margin from the demodulator output mutual information amount or the decoding unit input mutual information amount satisfying the required bit error rate.

  The wireless communication system of the present invention includes a base station and a mobile station, and the base station and the mobile station generate encoded bits by performing error correction encoding processing on information bit input, and digitally modulate the encoded bits. A radio communication system for transmitting and receiving a modulated signal, wherein a base station performs error correction coding, digital modulation, and a modulation scheme or coding rate based on a transmission margin notified from a reception processing unit. A transmission processing unit having means for transmitting by changing at least one of the above, means for receiving a digitally modulated signal from the mobile station, and extracting a transmission margin generated by the mobile station from the received signal A reception processing unit provided with a means, and a means for notifying a transmission margin to the error correction coding control unit is provided with either a transmission processing unit or a reception processing unit. Means for performing encoding, means for performing digital modulation, a transmission processing unit comprising means for transmitting a frame signal including feedback information, means for receiving a digitally modulated signal from a base station, and a received signal And a demodulating means for calculating coded bits from the means, a means for calculating an average mutual information amount with respect to a log likelihood ratio with respect to the coded bits, an average mutual information amount obtained by the average mutual information amount calculating means and a required bit Means for calculating transmission margin from decoding unit input mutual information amount or demodulating unit output mutual information amount satisfying error rate, means for notifying transmission processing unit of transmission margin, and logarithm for information bits obtained by error correction decoding unit A reception processing unit including a means for calculating a likelihood ratio and a means for calculating a logarithmic likelihood ratio determination result for an information bit, and calculating the transmission Characterized in that it comprises means for generating feedback information based on Jin to any one of the transmission processing unit or the reception processing unit.

  The wireless communication system of the present invention is the communication system described above, wherein at least one reception processing unit of the base station or the mobile station includes a demodulation unit, an average mutual information calculation unit, a transmission margin calculation unit, Correction decoding means, deinterleaving means, logarithm for information bits obtained by error correction decoding means, mutual information amount calculating means, margin calculating means arranged in at least one of the preceding stage and the succeeding stage of deinterleaving means Likelihood ratio or hard decision result calculation means is provided.

  Furthermore, the wireless communication system of the present invention is the communication system described above, wherein at least one reception processing unit of the base station or the mobile station includes a demodulation unit, an average mutual information calculation unit, a transmission margin calculation unit, Correction decoding means, deinterleaving means, logarithm for information bits obtained by error correction decoding means, mutual information amount calculating means, margin calculating means arranged in at least one of the preceding stage and the succeeding stage of deinterleaving means A likelihood ratio or hard decision result calculating means, an interference component detecting means, an erasure correcting means, a means for calculating an average mutual information amount with respect to a log likelihood ratio for the coded bits obtained by the erasure correcting means; Demodulator output mutual information or decoder input mutual information that satisfies the average mutual information obtained by the average mutual information calculation means and the required bit error rate Characterized in that it comprises a means for calculating a transmission margin from distribution amount.

  According to the present invention, the transmission rate can be improved by selecting an appropriate modulation method and coding rate even in a high antenna correlation environment or an environment where a narrow band interference signal is mixed.

It is a first block diagram according to an embodiment of the present invention. It is a 2nd block diagram which concerns on one Embodiment of this invention. It is a 3rd block diagram concerning one embodiment of the present invention. It is a block diagram of BS which concerns on one Embodiment of this invention. It is a block diagram of MS concerning one embodiment of the present invention. It is a figure for demonstrating the TDD frame which concerns on one Embodiment of this invention. It is a figure for demonstrating the transmission margin calculation example from the bit error rate characteristic with respect to the decoding part input mutual information amount in FIG. It is a figure for demonstrating the transmission margin calculation example from the bit error rate characteristic with respect to the decoding part input mutual information amount in each encoding rate in FIG. FIG. 3 is a diagram for explaining a transmission margin calculation example from a bit error rate characteristic with respect to a decoding unit input mutual information amount in FIG. 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Example 1 FIG. 1 is a first block diagram according to an embodiment of the present invention.
In the following, a MIMO (Multiple Input Multiple Output) transmission system composed of two transmitting antennas and two receiving antennas will be described, but the transmitting device and the receiving transmission have a single input single output (SISO) transmission. It can also be applied to SIMO (Single Input Multiple Output) transmission system in which only the system and the receiving device have two or more antennas, and MISO (Multiple Input Single Output) transmission system in which only the transmission device has two or more antennas. is there.

  1 includes a reception system 1 and a reception system 2, and includes an antenna 101-1 for the reception system 1, an antenna 101-2 for the reception system 2, and an RF (Radio Frequency: wireless) for the reception system 1. Unit 102-1, RF system 102-2 for receiving system 2, demodulator 103, deinterleaver unit 104-1 for receiving system 1, deinterleaver unit 104-2 for receiving system 2, MUX (Multiplexer) Unit 105, decoding unit 106, hard decision unit 107, mutual information amount calculation unit 108, and margin calculation unit 109.

The antenna 101-1 and the antenna 101-2 receive the radio signal transmitted from the transmission device, and the RF unit 102-1 and the RF unit 102-2 receive the carrier frequency bands received by the antenna 101-1 and the antenna 101-2, respectively. The received signal is down-converted from the received signal to a baseband signal, and the received signals Y ₁ and Y ₂ are output to the demodulator 103, respectively. In the present embodiment, the subscripts 1 and 2 indicate the receiving system 1 and the receiving system 2, respectively.

Ｌ^E _a,1は受信系統１における事前情報に基づく符号化ビットLLR、Ｌ^E _a,2は受信系統２における事前情報に基づく符号化ビットLLRであり、本一実施例では、送信信号に関する事前情報がないため、Ｌ^E _a,1＝Ｌ^E _a,2＝０であり、Ｌ^E _e,1＝Ｌ^E _p,1とＬ^E _e,2＝Ｌ^E _p,2となる。算出した復調部103の出力LLRＬ^E _e,1をデインタリーバ部１０４−１、Ｌ^E _e,2をデインタリーバ部１０４−２に出力する。Demodulation unit 103, by demodulating the received signal Y ₁ and Y ₂ obtained coded bits LLRL ^E _{p, 1} and L ^E _{p, 2} (subscript p indicates the first letter of Posterior ) Respectively. Here, the coded bit indicates a bit after error correction coding, and the bit before error correction coding is hereinafter referred to as an information bit. Bit LLR is defined as the logarithm of the ratio of the likelihood that the bit is 0 to the likelihood that it is 1.
For example, MLD (Maximun Likelihood Detection) obtains encoded bits LLRL ^E _{p, 1} and LLRL ^E _{p, 2} by using the distance between a received signal and a replica (ideal reception point calculated from a transmission path estimation result). . Using these encoded bits LLRL ^E _{p, 1} and LLRL ^E _{p, 2} , the outputs LLRL ^E _{e, 1} and LLRL ^E _{e, 2} of the demodulator 103 in each system (the subscript e is the initial of Extrinsic) Are calculated according to (Equation 1) and (Equation 2), respectively.

L ^E _{a, 1} is _a coded bit LLR based on prior information in the reception system 1, and L ^E _{a, 2} is _a coded bit LLR based on prior information in the reception system 2, and in this embodiment, prior to transmission signals. Since there is no information, L ^E _{a, 1} = L ^E _{a, 2} = 0, and L ^E _{e, 1} = L ^E _{p, 1} and L ^E _{e, 2} = L ^E _{p, 2} . The calculated output LLRL ^E _{e, 1} of the demodulator 103 is output to the deinterleaver unit 104-1, and L ^E _{e, 2} is output to the deinterleaver unit 104-2.

The deinterleaver unit 104-1 and the deinterleaver unit 104-2 are arranged so that the interleaving performed by the transmission apparatus is returned to the original order for the input L ^E _{e, 1} and L ^E _{e, 2 respectively} . Each process to be replaced is performed. The rearranged outputs L ^D _{a, 1} and L ^D _{a, 2} are input to the MUX unit 105.
The MUX unit 105 performs a process of rearranging the input L ^D _{a, 1} and L ^D _{a, 2 so} that the inter-system distribution process performed by the transmission apparatus returns to the original order. The input LLRL ^D _a of the decoding unit 106 that is the output after the rearrangement is output to the decoding unit 106 and the mutual information amount calculation unit 108.
Decoding unit 106 for being inputted LLRL ^D _a, for example, performs decoding processing by using a maximum a posteriori probability decoding, calculates output information bits LLRL ^D _u of the decoding unit 106, and outputs the hard decision unit 107 .
The hard decision unit 107 outputs a decoding result u obtained by a decision process such as a hard decision.

ここで、Ｈ（Ｘ）は相互情報量における事前エントロピー、Ｈ（Ｘ｜Ｙ）は事後エントロピーと呼ばれる。
確率変数Ｘにおける事前エントロピーＨ（Ｘ）は（式４）で求められる。

ここで、Ｐ（Ｘ＝ｉ）は確率変数Ｘがｉとなる確率を表す。Ｘを送信装置での符号化ビットＣ_ｎ（添え字のｎは符号化後のビット系列のインデックスを示す）とすると、Ｃ_nは２値｛０，１｝を取るため、Ｐ（Ｃ_n＝０）とＰ（Ｃ_n＝１）をそれぞれＰ₀とＰ₁とすると事前エントロピーＨ（Ｃ_n）は次（式５）で求められる。

Ｐ_０とＰ_１の生起確率は等確率を１／２とすると、Ｈ（Ｃ_n）は（式６）となる。

次に、事後エントロピーＨ（Ｃ_n｜Ｙ）は（式７）で求められる。

Mutual information amount calculation unit 108 based on the input LLRL ^D _a, and calculates the mutual information. An embodiment of the present invention is characterized by providing an apparatus capable of calculating an appropriate transmission margin even in various transmission path environments by calculating a transmission margin from the mutual information amount. Hereinafter, a process of calculating the mutual information amount from L ^D _a will be described, and a method of calculating the margin from the calculated mutual information amount will be described.
The mutual information I (X; Y) is obtained by (Equation 3) quantitatively indicating how much information regarding the random variable X is included in the event Y by knowing the value of the event Y.

Here, H (X) is called prior entropy in mutual information, and H (X | Y) is called posterior entropy.
Prior entropy H (X) in the random variable X is obtained by (Equation 4).

Here, P (X = i) represents the probability that the random variable X is i. Assuming that X is an encoded bit C _n at the transmitting device (subscript n indicates an index of the bit sequence after encoding), C _n takes binary {0, 1}, so P (C _n = 0) and P (C _n = 1) are P ₀ and P ₁ respectively, and the prior entropy H (C _n ) is obtained by the following (formula 5).

Assuming that the probability of occurrence of P ₀ and P ₁ is ½, H (C _n ) is expressed by (Equation 6).

Next, the posterior entropy H (C _n | Y) is obtained by (Expression 7).

（式３）に（式６）と（式８）を代入することにより、ｎ番目の符号化後のビット系列における相互情報量をＩ_n＝Ｉ（Ｃ_n；Ｌ^D _a（Ｃ_n））とすると、相互情報量Ｉ_nは（式９）となる。

Assuming that an event LLRL ^D _a (C _n ) of the decoding unit 106 corresponding to the coded bit C _n is an event Y, C _n is 0 under the condition that the input LLL ^D _a (C _n ) of the decoding unit 106 is obtained. And the probability of 1 being P ′ ₀ and P ′ ₁ respectively, the posterior entropy H (C _n | L ^D _a (C _n )) is given by (Equation 8).

By substituting (Equation 6) and (Equation 8) into (Equation 3), the mutual information amount in the n-th encoded bit sequence is _expressed as I _n = I (C _n ; L ^D _a (C _n )) When the mutual information amount I _n is (equation 9).

（式９）を式変形することにより、Ｐ’₀（Ｃ_n）とＰ’₁（Ｃ_n）はそれぞれ（式１１）（式１２）で表わされる。

（式９）に（式１１）と（式１２）を代入することにより、相互情報量Ｉ_nは（式１３）となる。

Thus, mutual information I _n is can be calculated by the bit probabilities P _'0 and P' _1. Assuming that the probabilities that the input coded bit C _{n of the} n-th decoding unit 106 is 0 and 1 are P ′ ₀ (C _n ) and P ′ ₁ (C _n ), respectively, the input LLL ^{D D} _{a of the} decoding unit 106 (C _n) is given by equation (10).

By transforming (Expression 9), P ′ ₀ (C _n ) and P ′ ₁ (C _n ) are expressed by (Expression 11) and (Expression 12), respectively.

By substituting the equation (9) and (Equation 11) (Equation 12), the mutual information I _n is (Equation 13).

Therefore, the mutual information amount calculation unit 108 can calculate from mutual information I _n inputted to the L ^D _a (C _n).
The method of calculating the mutual information I _n, for example, the Maclaurin expansion that does not require a conversion table or tables for calculating the mutual information I _n when the input LLRL ^D _a (C _n) is given of the decoding unit 106 The approximate calculation used can be mentioned. Since the mutual information amount of (Equation 13) is an instantaneous value, the variation is large. Accordingly, the average mutual information _IE that suppresses the variation by taking the sample average with respect to the encoding bit number N (N is a natural number) is calculated by (Equation 14), and is output to the margin calculation unit 109.

Since the mutual information input / output characteristics of the demodulation process depend on the transmission path environment such as the antenna correlation, the average mutual information _IE after the demodulation process is a value that takes into account the influence of the antenna correlation that is not considered in the reception CNR or the like. It becomes. Further, the average mutual information _IE calculated by the mutual information calculator 108 does not require a parameter related to antenna correlation.

1, taking into account the delay due to deinterleaver 104-1, 104-2 has been described a method of calculating a mutual information amount using the input LLRL ^D _a decoding unit 106, the output mutual demodulation unit 103 The amount of information and the input mutual information of the decoding unit 106 are the same as the amount of mutual information only by connecting the deinterleaver units 104-1 and 104-2 between them. Thus, for example, the output LLR demodulation unit 103 of the serial transmission and L ^E _e, if the average mutual information I _E coding bit number N calculated at sufficiently Okere, instead of the input LLRL ^D _a of the decoding unit 106 Since the same value is obtained even when the output LLRL ^E _e of the demodulator 103 is used, I _E may be calculated using the output LLRL ^E _e of the demodulator 103.
In addition, the example has been described in which the MLL unit 105 calculates the mutual information amount by bundling the inputs LLRL ^D _{a, 1} and L ^D _{a, 2} of the decoding unit 106 of each system, but the average mutual information I _E for each system. May be calculated.

復号処理の相互情報量入出力特性は、伝送路特性や受信ＣＮＲに関わらず、誤り訂正符号化方式のみに従い、一意に決定される。この入出力特性より、復号部１０６の入力相互情報量に対するビット誤り率が算出可能であることは周知の技術であり、図７のようにグラフで描くことが可能である。例えば、送信装置で畳み込み符号を用いる場合、符号化率ｒのみが可変のパラメータであれば、各符号化率（例えばｒ＝１／２，２／３，３／４，５／６）に応じた所要ビット誤り率γを達成する相互情報量Ｉ_Rは事前に予め算出可能である。従って、各符号化率での相互情報量Ｉ_Rをテーブルとして記憶し、参照することにより、伝送中の符号化率と異なる符号化率の伝送マージンＩ_Mも算出することが可能である。例えば、図８に示すように、送信装置で設定中の符号化率ｒ＝１／２における伝送マージンＩ_M,r12と異なる符号化率ｒ＝２／３における伝送マージンＩ_M,r23を同時に算出可能となる。In the margin calculation unit 109, based on the input average mutual information I _E and the mutual information I _R that achieves a required bit error rate γ or less obtained by computer simulation or the like, the transmission margin I _M is expressed by (Equation 15). Can be sought.

The mutual information input / output characteristics of the decoding process are uniquely determined according to only the error correction coding method regardless of the transmission path characteristics and the received CNR. It is a well-known technique that the bit error rate with respect to the input mutual information amount of the decoding unit 106 can be calculated from this input / output characteristic, and can be drawn in a graph as shown in FIG. For example, when a convolutional code is used in the transmission apparatus, if only the coding rate r is a variable parameter, it depends on each coding rate (for example, r = 1/2, 2/3, 3/4, 5/6). The mutual information amount I _R that achieves the required bit error rate γ can be calculated in advance. Therefore, by storing and referring to the mutual information amount I _R at each coding rate as a table, it is possible to calculate a transmission margin I _M having a coding rate different from the coding rate during transmission. For example, as shown in FIG. 8, a transmission margin I _{M, r23} in the transmission margin I _{M, r12} and different coding rate r = 2/3 in the coding rate r = 1/2 being set at the transmitting device simultaneously calculated It becomes possible.

Further, similarly to the coding rate, the transmission margin in each modulation method can be calculated simultaneously. By computer simulation or the like, the relationship with the LLR of the demodulator 103 output in each modulation method can be obtained.

By displaying the transmission margin I _M obtained from (Equation 15) on, for example, a display, the user using the receiving apparatus can know the transmission margin I _M.
The above are representative of transmission margin I _M using mutual information, may provide information analogous thereto. For example, a warning alarm is notified when the transmission margin I _M approaches zero.

According to the above-described embodiment, the average mutual information I _E is calculated from the input LLRL ^D _a of the decoding unit 106, and the transmission margin I _M is calculated based on the obtained average mutual information I _E. It is possible to provide an appropriate transmission margin considering the influence.

(Example 2) Next, Example 2 is demonstrated using FIG.
FIG. 2 is a second block diagram according to an embodiment of the present invention.
About the processing part which attached | subjected the code | symbol same as FIG. 1, since it is the same operation | movement as description of a 1st block diagram, description is abbreviate | omitted. The second block diagram is characterized in that the receiving apparatus described in the first block diagram is provided with turbo signal processing for performing iterative processing a plurality of times.
Hereinafter, a description will be given of a MIMO transmission system including two transmission antennas and two reception antennas, but the present invention can also be applied to a SISO transmission system, a SIMO transmission system, and a MISO transmission system.

  In the turbo signal processing, the demodulation unit 201 and the decoding unit 204 are connected via the deinterleaver units 202-1 and 202-2 and the interleaver units 206-1 and 206-2, and the demodulation unit 201 and the decoding unit are performed while performing iterative processing. This is a technique for improving the decoding performance by passing the encoded bit LLR between the two.

Similarly to the first block diagram, the demodulating unit 201 outputs Y ₁ and Y ₂ output from the RF units 102-1 and 102-2 in each system and interleavers 206-1 and 206-2 in each system. Based on the input LLRLE ^E _{a, 1} and L ^E _{a, 2 of the} demodulator 201 based on the output prior information, the outputs LRL ^E _{e, 1} and L ^E _{e, 2} of the demodulator 201 in each system are expressed by (Equation 1) And (Equation 2). Output of the resulting demodulator 201 LLRL _{^E e, 1} is deinterleaver _202-1, L _{^E e, 2} outputs the deinterleaver 202-2. However, since L ^E _{a, 1} and L ^E _{a, 2} are not obtained before the first iteration, L ^E _{e, 1} = L ^E _{p, 1} and L ^E _{e, 2} = L ^E _{p, 2} .

The deinterleaver units 202-1 and 202-2 perform a process of rearranging the interleaving performed by the transmission device so that the input L ^E _{e, 1} and L ^E _{e, 2} are returned to the original order. Apply. The input LLRL ^D _{a, 1} and L ^D _{a of the} rearranged decoding unit 204 are output to the MUX unit 203.
The MUX unit 203 performs a process of rearranging the inter-system distribution process performed by the transmission apparatus so that the input L ^D _{a, 1} and L ^D _{a, 2} are returned to the original order. And it outputs the input LLRL ^D _a decoding unit 204 is output after reordering the decoding unit 204 and the mutual information amount calculation unit 108.

Ｌ^D _aは復号部２０４の事前情報に基づく符号化ビットLLRである。算出した復号部２０４の出力LLRＬ^D _pをＤＥＭＵＸ（DeMultiplexer：デマルチプレクサ）部２０５に出力する。
ＤＥＭＵＸ部２０５は、入力されたＬ^D _pに対して、送信装置で施された系統間振り分けと同じ処理を施す。振り分け後の受信系統１に対する出力Ｌ^D _e,1と受信系統２に対する出力Ｌ^D _e,2をそれぞれインタリーバ部２０６−１，２０６−２に出力する。The decoding unit 204 performs a decoding process on the input L ^D _a using, for example, maximum a posteriori probability decoding, calculates a coded bit LLRL ^D _p based on the posterior information, and outputs the output LLL ^{D D of the} decoding unit 204 _e is calculated according to (Equation 16).

L ^D _a is _a coded bit LLR based on the prior information of the decoding unit 204. The calculated output LLRL ^D _p of the decoding unit 204 is output to a DEMUX (DeMultiplexer) unit 205.
The DEMUX unit 205 performs the same processing as the inter-system allocation performed by the transmission apparatus on the input L ^D _p . Output for output to the reception system 1 of the allocated L ^D _{e, 1} and receiving system ₂ L ^D _e, 2 respectively outputted to the interleaver unit 206-1 and 206-2.

Interleavers 206-1 and 206-2 perform the same rearrangement process on the input L ^D _{e, 1} and L ^D _{e, 2} as in the interleaving performed by the transmission apparatus. First iteration process by outputting the demodulation unit after the rearrangement input LLRL ^E _{a, 1} and L ^E _{a, 2} to demodulation section 201 is completed.

In the second and subsequent iterations, the demodulator 201 outputs Y ₁ and Y ₂ output from the RF units 102-1 and 102-2 in each system and the interleaver unit 206- in each system, as in the first embodiment. 1, 206-2, from the input LLRLE ^E _{a, 1} and L ^E _{a, 2 of the} demodulator 201 based on the prior information output from 206-2, the output LLLLE ^E _{e, 1} and L ^E _{e, 1} of the demodulator 201 in each system ₂ is calculated again according to (Equation 1) and (Equation 2). By using iterative processing, the prior information about the coded bits is increased by using the outputs LLRL ^E _{e, 1} and L ^E _{e, 2} of the demodulation unit 201 in each system obtained from the decoding unit 204 (in other words, coding The demodulation process is performed in a state where the ambiguity regarding the bit is reduced). Accordingly, the average mutual information I _E obtained from the outputs LLRL ^E _{e, 1} and L ^E _{e, 2 of} the demodulator 201 increases.

After repeating the above series of processes a predetermined number of times, the decoding unit 203 performs a decoding process on L ^D _a using, for example, maximum a posteriori probability decoding as in the first embodiment, and sets L ^D _u to Calculate and output to the hard decision unit 107.
The hard decision unit 107 outputs a decoding result u obtained by a decision process such as a hard decision.

The mutual information amount calculation unit 108 calculates the average mutual information amount _IE according to (Equation 14) in the same manner as the operation description of the first block diagram of FIG. Since the description of the operation of the second block diagram of FIG. 2 is based on turbo signal processing, the average mutual information _IE may be calculated for each iteration, or the average mutual information I at any number of iterations of 1 or more. _E may be calculated.

The margin calculation unit 108 calculates a transmission margin I _M from the input average mutual information I _E according to (Equation 15) as in the description of the operation of the first block diagram. For example, repeated when the processing times were maximum twice, iterate before the average mutual information between the transmission margin respectively I _{E, 0} and I _{M, 0,} iterate first average mutual information between the transmission margin respectively If I _{E, 1} and I _{M, 1} and the average mutual information amount and transmission margin for the second iteration are I _{E, 2} and I _{M, 2} , respectively, the relationship is as shown in FIG. Along with the iterative processing, the average mutual information amount increases, so the transmission margin also increases.

The description of the operation of the second block diagram of a more calculation, when the receiving apparatus is provided with a turbo signal processing for performing multiple iterations, the average mutual information I _E the input LLRL ^D _a of the decoding unit 204 and, by calculating the transmission margin I _M based on the average mutual information I _E, it is possible to provide a suitable transmission margin in accordance with the influence of the antenna correlation.

(Example 3) Next, Example 3 is demonstrated using FIG.
FIG. 3 is a third block diagram according to one embodiment of the present invention.
About the processing part which attached | subjected the code | symbol same as FIG. 1, since it is the same operation | movement as a 1st block diagram, description is abbreviate | omitted. The third block diagram is a configuration including an erasure correction unit for an interfered signal in order to suppress deterioration of the bit error rate due to mixing of an interference signal from another system. Hereinafter, the description will be made assuming a receiving apparatus that receives an OFDM (Orthogonal Frequency Division Multiplexing) modulated signal, but the present invention is also applicable to single carrier modulation.

In the interference detection unit 301, for example, the CVI (Carrier Variance Information) disclosed in Non-Patent Document 2 is used to detect the signal Y _l of the l-th subcarrier mixed with the interference wave, and the erasure correction unit 302. If the interfered power of Y ₁ is larger than the predetermined threshold value than the predetermined threshold value, the erasure correction process is performed. The erasure correction processing indicates data erasure processing, and Y _l is converted to 0 or a value close to 0. And it outputs the signal Y _d after erasure correction to the demodulator 103.

If erasure correction processing is not performed, the LLR value may be low due to interference, and the LLR value may be erroneously recognized as the reception level increases due to interference. This will adversely affect the decryption result. Therefore, the reception characteristics can be improved by reducing the likelihood of the subcarrier mixed with the interference wave by erasure correction. By contrast in erasure correction processing, since the sample to be input LLRL ^D _a = 0 of the decoding unit 106 occurs, erasure average mutual information I _E after correction is to reduce as compared to when the interference wave is not mixed The transmission margin I _M calculated by Equation 15 also decreases.

It is also possible to display the transmission margin calculated without performing the erasure correction process on the display and confirm the amount of deterioration of the mutual information amount due to the interfered signal.
In FIG. 3, the interference detection unit 301 and the erasure correction unit 302 are provided before the demodulation unit 103, but may be provided after the demodulation unit 103.
By calculating the mutual information I _M for the received signal Y _{d on} which the erasure correction of the interfered signal has been performed according to the operation explanation of the third block diagram described above, the reception level of the interfered signal can be reduced. An appropriate transmission margin can be designed even when the fluctuation is large.

(Example 4) Next, Example 4 is demonstrated using FIG.
The fourth embodiment includes the erasure processing correction unit described in the third embodiment, feeds back the transmission margin generated by the reception device to the transmission device, and the transmission device has a function of performing AMC based on the feedback information. It is a configuration.
Example 4 described below describes a wireless device having a frame configuration of a TDD (Time Division Duplex) system, but also in a wireless device having a frame configuration of an FDD (Frequency Division Duplex) system. Applicable.

A configuration of a wireless system according to the fourth embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4 is a block diagram of a BS according to an embodiment of the present invention.
FIG. 5 is a block diagram of an MS according to an embodiment of the present invention.
The wireless system of the fourth embodiment includes a BS (Base Station) 400-1 and an MS (Mobile Station) 400-2, and performs wireless communication between the BS 400-1 and the MS 400-2.

  Here, a frame configuration example of the TDD system used in the fourth embodiment will be described with reference to FIG. As shown in FIG. 6, one frame includes a DL (Down Link) subframe for transmission from the BS to the MS and a UL (Up Link) subframe for transmission from the MS to the BS. A TTG (Transmit Transition Gap) and an RTG (Receive Transition Gap) for switching processes are provided. The DL subframe includes a preamble, FCH (Frame Control Header), and DL data, and the UL subframe includes CQICH (Channel Quality Information Channel) and UL data.

BS 400-1 includes BS transmission processing section 401-1 and BS reception processing section 402-1. Hereinafter, the subscripts t1 and r1 indicate the BS transmission processing unit 401-1 and the BS reception processing unit 402-1 respectively.
The BS transmission processing unit 401-1 includes an encoding unit 403-1, an interleaver unit 404-1, a modulation unit 405-1, a frame configuration unit 406-1, and an adaptive modulation and coding control unit 407, and includes an encoding unit 403-. 1, the input information bit b _t1 is subjected to error correction coding processing to output a coded bit C _t1 , and the interleaver 404-1 has a predetermined order with respect to the input C _t1 . and outputs coded bits C _t1 after rearranged C _t1, relative to C _{i, t1} entered the modulation unit 405-1, and outputs a modulated signal X _t1 performs modulation processing, frame configuration section 406-1 against X _t1 entered the outputs X _'t1 obtained by a frame which combines such a preamble and FCH for frame synchronization to the RF unit 408-1, antenna 409-1 More wireless signal transmission To.

Adaptive modulation and coding control unit 407 generates MCS information S _t1 based on the transmission margin I _{M, r1} obtained from BS reception processing unit 402-1, an output to the encoding unit 403-1 and modulation unit 405-1 To do. Based on the MCS information S _t1, the encoding unit 403-1 in the coding rate in the next frame, it sets the modulation method in the modulation unit 405-1.

BS reception processing section 402-1 includes frame extraction section 410-1, interference detection section 411-1, erasure processing section 412-1, demodulation section 413-1, deinterleaver section 414-1, and decoding section 415-1. , Comprising a hard decision unit 416-1 and a CQICH extraction unit 417, and the signal received by the antenna 409-1 is down-converted to a baseband signal by the RF unit 408-1, and the Y input by the frame extraction unit 410-1 'establishes frame synchronization with respect to _r1, the frame synchronization interference detector the received signal Y _r1 after 411-1, and outputs the erasure correction unit 412-1 and the CQICH extractor 417.

The interference detection unit 411-1 detects the signal Y _{l, r1} of the l-th subcarrier mixed with the interference wave with respect to the input Y _r1 as in the third embodiment, and the erasure correction unit 412-1 If the interfered power of Y _{l, r1} is larger than the predetermined threshold value from the predetermined threshold value, erasure correction similar to that in the third embodiment is performed. The signal Y _{d, r1} after erasure correction is output to the demodulator 413-1.

The demodulator 413-1 calculates the output LLRL ^E _{e, r1} of the demodulator 413-1 by demodulation processing in the same manner as in the first embodiment _, and outputs it to the deinterleaver 414-1. The deinterleaver unit 414-1 receives the input LLRL ^E _{a, r1} of the decoding unit 415-1 that has been subjected to the rearrangement process so that the bit rearrangement performed by the interleaver 404-2 in the MS transmission processing unit is restored. It outputs to the decoding part 415-1.

The decoding unit 415-1 performs the same decoding process on the input L ^D _{a, r1} as in the first embodiment, calculates the information bit LLRL ^D _{u, r1,} and outputs it to the hard decision unit 413-1. The hard decision unit 413-1 outputs a decoding result u _r1 obtained by a decision process such as hard decision for the input L ^D _{u, r1} .
The CQICH extraction unit 417 extracts CQICH included in a UL subframe to be described later, and outputs a transmission margin I _{M, r1} included in the CQICH to the adaptive modulation and coding control unit 407.

The MS 400-2 includes an MS transmission processing unit 401-2 and an MS reception processing unit 402-2. Hereinafter, the subscripts t2 and r2 indicate the MS transmission processing unit 401-2 and the MS reception processing unit 402-2, respectively.
The MS reception processing unit 402-2 includes a frame extraction unit 410-2, an interference detection unit 411-2, an erasure correction unit 412-2, a demodulation unit 413-2, a deinterleaver unit 414-2, a decoding unit 415-2, a hard unit. A determination unit 416-2, a mutual information amount calculation unit 418, and a margin calculation unit 419 are provided. A signal received by the antenna 408-2 is down-converted to a baseband signal by the RF unit 407-2, and a frame extraction unit 409-2 Then, frame synchronization is performed on the input Y ′ _r2 , and the received signal Y _r2 after the frame synchronization is output to the interference detection unit 411-2 and the erasure correction unit 412-2.

The interference detection unit 411-2 detects the signal Y _{l, r2} of the l-th subcarrier mixed with the interference wave with respect to the input Y _r2 as in the third embodiment, and the erasure correction unit 411-2 When the interference power of Y _{l, r2} is larger than the predetermined threshold, erasure correction is performed. The signal Y _{d, r2} after erasure correction is output to the demodulator 413-2.

The demodulator 413-2 calculates the encoded bit LLRL ^E _{e, r2} of the output of the demodulator 413-2 and outputs it to the deinterleaver 414-2 by the same demodulation processing as in the first embodiment. The deinterleaver unit 414-2 decodes the input LLRL ^D _{a, r2} of the decoding unit 415-2 that has been subjected to the rearrangement process so that the bit rearrangement performed by the interleaver unit in the BS transmission processing unit is restored. It outputs to 415-2.

The decoding unit 415-2 performs the same decoding process as in the first embodiment on the input L ^D _{a , r2} to calculate the information bit LLL L ^D _{u, r2} and outputs it to the hard decision unit 413-2. Hard decision unit 413-2 outputs the decoded results u _r2 obtained by the determination process, such as the hard decision with respect to L ^D _{u, r2} entered.
The mutual information amount calculation unit 418 calculates the average mutual information amount I _{E, r2} for the input L ^D _{a, r2} as in the first embodiment, and outputs it to the margin calculation unit 419.
The margin calculation unit 419 calculates a transmission margin I _{M, r2} based on the mutual information amount for the input I _{E, r2} as in the first embodiment, and generates a CQICH generation unit in the MS transmission processing unit 401-2. Output to 420.

CQICH generation unit 420 outputs the I _{M, r2} input feedback information and combinations of such channel quality information, the feedback information f _t2 to frame configuration section 406-2.
The MS transmission processing unit 401-2 includes an encoding unit 403-2, an interleaver unit 404-2, a modulation unit 405-2, a frame configuration unit 406-2, and a CQICH generation unit 420. The encoding unit 403-2 receives an input. The encoded information bit b _t2 is subjected to error correction coding processing to output a coded bit C _t2 , and the interleaver 404-2 receives C _t2 in a predetermined order with respect to the inputted C _t2. Encoded bits C _{i, t2} are output, the modulation unit 405-1 performs modulation processing on the input C _{i, t2} and outputs a modulation signal X _t2 , and a frame configuration unit 406-1 against X _t2 entered in the X _'t2 obtained by constituting the UL sub-frame is output to the RF unit 407-2 combines the like ranging or CQICH, a radio signal from the antenna 408-2 Send.

In this way, in this embodiment, the transmission margin I _{M, r2} based on the average mutual information I _{E, r2} obtained from the input LLL ^D _{a, r2} of the decoding unit 415-2 is used for the modulation scheme and coding rate in AMC. Therefore, even when the received signal quality due to the interference signal is deteriorated, an appropriate modulation scheme and coding rate can be set, and the transmission rate can be improved.

  In the fourth embodiment, the configuration example in which only the BS 400-1 includes the AMC is described, but the MS 400-2 may include the AMC. Moreover, the CQICH extraction unit 417 and the adaptive modulation control unit 407 may be provided in either one of the BS transmission processing unit 401-1 and the BS reception processing unit 402-1.

  In the fourth embodiment, the wireless system including the erasure correction processing described in the third embodiment is described as an example extended to two-way communication with a transmission device including an AMC. However, the first embodiment and the second embodiment are also described. It is extensible.

  The radio communication system according to the embodiment of the present invention can improve the transmission rate by selecting an appropriate modulation scheme and coding rate even in a high antenna correlation environment or an environment where a narrow band interference signal is mixed.

  Although the present invention has been described in detail above, it is needless to say that the present invention is not limited to the radio communication system described here, and can be widely applied to radio communication systems other than those described above.

  By controlling AMC using a transmission margin, the present invention can be applied to a high antenna correlation environment or an application in which a narrow band interference signal is mixed. This application claims the benefit of priority based on Japanese Patent Application No. 2015-102881 filed on May 20, 2015, the entire disclosure of which is incorporated herein by reference.

  101: receiving antenna, 101-1: receiving antenna in receiving system 1, 101-2: receiving antenna in receiving system 2, 102: RF unit, 102-1: RF unit in receiving system 1, 102-2: receiving system 2 , 103: demodulation unit, 104: deinterleaver unit, 104-1: deinterleaver unit in reception system 1, 104-2: deinterleaver unit in reception system 2, 105: MUX unit, 106: decoding unit, 107 : Hard decision unit, 108: mutual information calculation unit, 109: margin calculation unit, 201: demodulation unit equipped with turbo signal processing, 202-1: deinterleaver unit in receiving system 1 equipped with turbo signal processing, 202- 2: Deinterleaver unit in receiving system 2 with turbo signal processing, 203: MUX unit with turbo signal processing, 204 Decoding unit with turbo signal processing, 205: DEMUX unit with turbo signal processing, 206-1: Interleaver unit in reception system 1 with turbo signal processing, 206-2: Reception system 2 with turbo signal processing , 301: interference detection unit, 302: erasure correction unit, 400-1: BS, 400-2: MS, 401-1: BS transmission processing unit, 401-2: MS transmission processing unit, 402-1: BS reception processing unit, 402-2: MS reception processing unit, 403-1: encoding unit of BS transmission processing unit, 403-2: encoding unit of MS transmission processing unit, 404-1: interleaver of BS transmission processing unit 404-2: MS transmission processing unit interleaver 405-1: BS transmission processing unit modulation unit 405-2: MS transmission processing unit modulation unit 406-1: BS transmission processing unit frame 406-2: MS transmission processing unit frame configuration unit, 407: BS transmission processing unit adaptive modulation and coding control unit, 408-1: BS RF unit, 406-2: MS RF unit, 409 -1: BS antenna, 406-2: MS antenna, 410-1: BS extraction processing unit frame extraction unit, 410-2: MS reception processing unit frame extraction unit, 411-1: BS reception processing unit Interference detection unit, 411-2: interference detection unit of MS reception processing unit, 412-1: erasure correction unit of BS reception processing unit, 412-2: erasure correction unit of MS reception processing unit, 413-1: BS reception processing Demodulation unit, 413-2: demodulation unit of MS reception processing unit, 414-1: deinterleaver unit of BS reception processing unit, 414-2: deinterleaver unit of MS reception processing unit, 415-1: BS reception processing Decoding unit 415- : Decoding unit of the MS reception processing unit, 416-1: Hard decision unit of the BS reception processing unit, 416-2: Hard decision unit of the MS reception processing unit, 417: CQICH extraction unit of the BS reception processing unit, 418: MS reception Mutual information amount calculation unit of processing unit, 419: margin calculation unit of MS reception processing unit, 420: CQICH extraction unit of MS transmission processing unit.

Claims (6)

A receiving apparatus of an FPU system that generates a coded bit by error correction coding processing of an information bit input and receives a modulated signal digitally modulated with respect to the coded bit,
Demodulation means for calculating a log-likelihood ratio for encoded bits of error correction encoding from the received signal;
Against log-likelihood ratio for the coded bits, average means for calculating a mutual information, the average mutual information between during transmission from the required bit satisfies the error rate decoding means input mutual information or demodulation means output mutual information Means for calculating a transmission margin in a coding rate or modulation scheme different from a transmission margin in a coding rate or modulation scheme of
Error correction decoding means corresponding to the error correction encoding from the log likelihood ratio for the input encoded bits;
Display means for displaying on a display; and a transmission margin calculated by the means for calculating the transmission margin is displayed on the display means. An information bit input is generated by an error correction encoding process to generate encoded bits, and a digitally modulated signal is received with respect to the encoded bits rearranged in a predetermined order by an interleaver having interleaving means. 1. The receiving device according to 1, wherein
Demodulation means for calculating a log-likelihood ratio for the coded bits based on the received signal and prior information;
A deinterleaver unit comprising deinterleave means for rearranging the order of the data rearranged by the interleaver on the transmission side to the original order;
The deinterleaver unit includes a mutual information amount calculating means and a margin calculating means arranged in at least one of the preceding stage and the succeeding stage,
When the mutual information amount calculating means is arranged in the preceding stage of the deinterleaver unit, the average mutual information amount with respect to the log likelihood ratio with respect to the encoded bit of the demodulating unit output input to the deinterleaver unit And the average mutual information amount with respect to the log likelihood ratio for the encoded bits of the decoding means input after the reordering by the deinterleaver unit Having means for calculating
The margin calculating means comprises means for calculating a transmission margin from the average mutual information amount obtained by the average mutual information amount calculating means and the demodulating means output mutual information amount or the decoding means input mutual information amount satisfying the required bit error rate,
Decoding means for calculating a log likelihood ratio for the encoded bit based on external information by a decoding process corresponding to the error correction encoding from the log likelihood ratio for the input encoded bit;
An interleaver comprising interleaving means for rearranging the encoded bits of the decoding means output in a predetermined order, and means for inputting the interleaver output as prior information of the demodulation means,
A receiving apparatus comprising: means for calculating a log-likelihood ratio or a hard decision result for information bits obtained by the error correction decoding means. The receiving device according to claim 1 or 2, wherein
An interference detection means and an erasure correction means arranged in at least one of the preceding stage and the subsequent stage of the demodulation means,
The interference detecting means has means for detecting an interference component from a received signal when arranged in the preceding stage of the demodulating means, and is output from the demodulating means when arranged in the subsequent stage of the demodulating means. Means for detecting interference components for the coded bits;
When the erasure correction unit is arranged in the preceding stage of the demodulation unit, the received signal is input to the reception signal input to the demodulation unit based on the detection result of interference obtained by the interference detection unit. Has means for performing erasure correction processing on
When arranged in the latter stage of the demodulating means, the coding based on the detection result of the interference obtained by the interference detecting means with respect to the log likelihood ratio for the coded bit output from the demodulating means. Means for performing erasure correction processing to log likelihood ratio for bits,
A means for calculating an average mutual information amount with respect to a log likelihood ratio for the coded bits after the erasure correction processing, and a demodulation satisfying the average mutual information amount obtained by the average mutual information amount calculating means and a required bit error rate. A receiving apparatus comprising means for calculating a transmission margin from the means output mutual information amount or the decoding means input mutual information amount. A base station and a mobile station are provided, and the base station and the mobile station generate encoded bits by error correction encoding processing of information bit input, and transmit / receive a modulated signal digitally modulated with respect to the encoded bits An FPU wireless communication system,
In the base station, based on the transmission margin notified from the means for performing error correction coding, the means for performing digital modulation, and the reception processing unit, at least one of the modulation scheme and the coding rate is changed and transmitted. A transmission processing unit comprising means;
A reception processing unit comprising: means for receiving a digitally modulated signal from the mobile station; and means for extracting a transmission margin generated by the mobile station from the received signal.
Means for notifying the transmission margin to the error correction coding control unit comprises either the transmission processing unit or the reception processing unit,
In the mobile station, a transmission processing unit including means for performing error correction coding, means for performing digital modulation, means for transmitting a frame signal including feedback information,
Means for receiving a digitally modulated signal from the base station and demodulation means for calculating coded bits from the received signal, and calculating an average mutual information amount for a log likelihood ratio for the coded bits It means a transmission margin in the coding rate or modulation scheme in the transmission from the average mutual information decoding unit input mutual information satisfies the average mutual information and the required bit error rate obtained by the calculating means or demodulator output mutual information Means for calculating a transmission margin in a coding rate or modulation scheme different from the coding rate or modulation scheme in transmission, display means for displaying the transmission margin calculated by the means for calculating the transmission margin, and the transmission Means for notifying the transmission margin to the processing unit and calculating a log likelihood ratio for the information bits obtained by the error correction decoding means. When, a reception processing unit having means for calculating a decision result of the log-likelihood ratio for the information bits,
A wireless communication system, comprising means for generating feedback information based on the calculated transmission margin in either the transmission processing unit or the reception processing unit. A wireless communication system according to claim 4,
The reception processing unit of at least one of the base station or the mobile station includes a demodulation unit, an average mutual information calculation unit, a transmission margin calculation unit, a correction decoding unit, a deinterleaving unit, and a deinterleaving unit. It comprises a mutual information amount calculating means, a margin calculating means, a decoding means, and a log likelihood ratio or hard decision result calculating means for information bits obtained by the error correction decoding means, which are arranged in at least one of the preceding stage and the succeeding stage. A wireless communication system. A wireless communication system according to claim 4,
The reception processing unit of at least one of the base station or the mobile station includes a demodulation unit, an average mutual information calculation unit, a transmission margin calculation unit, a correction decoding unit, a deinterleaving unit, and a deinterleaving unit. Mutual information amount calculation means and margin calculation means, decoding means, log likelihood ratio or hard decision result calculation means for information bits obtained by error correction decoding means, and interference component detection Means, erasure correction means, means for calculating an average mutual information amount with respect to a log likelihood ratio for the coded bits obtained by the erasure correction means, and average mutual information obtained by the average mutual information amount calculation means A means for calculating a transmission margin from the mutual information amount output from the demodulation means or the mutual information amount input from the decoding means that satisfies the required amount and the required bit error rate. Wireless communication system according to claim Rukoto.

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