WO2007003096A1 - Receiver and radio communication system for reducing the rate of frequency multiplex - Google Patents

Receiver and radio communication system for reducing the rate of frequency multiplex Download PDF

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Publication number
WO2007003096A1
WO2007003096A1 PCT/CN2006/001340 CN2006001340W WO2007003096A1 WO 2007003096 A1 WO2007003096 A1 WO 2007003096A1 CN 2006001340 W CN2006001340 W CN 2006001340W WO 2007003096 A1 WO2007003096 A1 WO 2007003096A1
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WO
WIPO (PCT)
Prior art keywords
receiver
interference suppression
unit
space
transmitter
Prior art date
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PCT/CN2006/001340
Other languages
French (fr)
Chinese (zh)
Inventor
Ruobin Zheng
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to CNB2005100807257A priority Critical patent/CN100557988C/en
Priority to CN200510080725.7 priority
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2007003096A1 publication Critical patent/WO2007003096A1/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks ; Receiver end arrangements for processing baseband signals
    • H04L25/03006Arrangements for removing intersymbol interference
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04JMULTIPLEX COMMUNICATION
    • H04J11/00Orthogonal multiplex systems, e.g. using WALSH codes
    • H04J11/0023Interference mitigation or co-ordination
    • H04J11/0026Interference mitigation or co-ordination of multi-user interference
    • H04J11/003Interference mitigation or co-ordination of multi-user interference at the transmitter
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks ; Receiver end arrangements for processing baseband signals
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L25/03178Arrangements involving sequence estimation techniques
    • H04L25/03305Joint sequence estimation and interference removal
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/03Shaping networks in transmitter or receiver, e.g. adaptive shaping networks ; Receiver end arrangements for processing baseband signals
    • H04L25/03006Arrangements for removing intersymbol interference
    • H04L2025/0335Arrangements for removing intersymbol interference characterised by the type of transmission
    • H04L2025/03426Arrangements for removing intersymbol interference characterised by the type of transmission transmission using multiple-input and multiple-output channels

Abstract

A receiver for reducing the rate of frequency multiplex and a related communication system. The receiver can be a receiver provided with single interference suppression or a receiver provided with multiple decoding unit interference suppression, comprising: a signal receiving and processing unit and an interference suppression and cancellation unit. The signal reception and processing unit is arranged to demodulate and demap the signals and then channel-decode the resulted signals. The interference suppression and cancellation unit is arranged to perform suppression and cancellation process on the interferences between respective received signals. The receiver provided with single interference suppression or the receiver provided with multiple decoding unit interference suppression is concluded by a base station or a user equipment in the radio communication system. The various existing cofrequency interferences can be reduced or even canceled according to the present invention. The distance of multiplex can be shortened efficiently. The rate of frequency multiplex can be reduced and the capacity of a cellular communication system may be increased.

Description

 Receiver and wireless communication system for reducing frequency reuse rate

 The present invention relates to the field of wireless communication technologies, and in particular, to a wireless communication technology for reducing a frequency reuse rate.

Background of the invention

 It has been theoretically proved that the use of multiple transmit antennas can split the wireless channel into multiple parallel narrowband channels, which has the potential to increase the channel bit transmission rate, and the research results show that the channel capacity increases linearly with the number of antennas. Compared to receive diversity and smart antennas, the MIM0 (Multiple Input Multiple Output) system not only provides diversity gain and array gain, but also increases system capacity in SDM (spatial multiplexing).

 BLAST is a way to increase the bandwidth efficiency by using spatial multiplexing technology in wireless communication, which is called Bell Labs layered space-time structure. The BLAST system uses multiple antennas to simultaneously transmit parallel data streams in the same frequency band, and utilizes rich multipath to propagate different data streams and separate them at the receiver to achieve spatial diversity.

 The principle of BLAST is shown in Figure 1. Multiple transmitters use the same modulation scheme, and multiple receivers use the same demodulation scheme. BLAST divides the data stream of a single user into multiple substreams and simultaneously transmits these parallel substreams using multiple antennas, all of which are transmitted in the same frequency band, so the spectrum is highly efficient to use. Multiple copies of the required data enter the channel (transmitting antenna) and have multiple outputs (receiving antennas). At the receiver end, multiple antennas pick out a plurality of transmitted data substreams and their scattered replicas, each receiving antenna receives all transmitted data substreams that are superimposed together, and can utilize complex signal processing techniques to pass The difference in these subchannels separates the data substream and detects it.

 Since the number of antennas, whether transmitter or receiver, is limited, increasing the diversity gain and increasing the transmission rate are a contradiction. STC (space-time code) and SFC (space-frequency code) can better resolve this contradiction.

 The space-time code utilizes the spatial diversity that the multi-antenna system can provide, and its performance depends on the number of antennas of the system and the spatial and temporal coding of the signal, including space-time block codes and space-time trellis codes. These codes are designed to assume non-multipath channel conditions, which are narrowband codes, and the maximum achievable diversity gain is equal to the product of the number of transmit antennas and the number of receive antennas.

 Under wideband multipath channel conditions, the performance of space-time code is not optimal because it only utilizes spatial diversity and does not utilize channel frequency diversity provided by multipath. Therefore, in the multipath environment, the coding problem of multi-antenna systems based on OFDM (Orthogonal Frequency Division Multiplexing) is studied. The concept of space-frequency codes is proposed. The potential diversity gain of these codes is the number of transmit antennas and reception. The product of the number of antennas and the channel impulse response length (channel multipath number).

From the coherence time and coherence bandwidth of the fading channel, the space-time code requires that the channel fading time response remains approximately constant within one code block period spanning several OFDM characters, that is, the larger the phase time is, the better; It is required that the channel fading frequency response of one code block spanning several subcarriers remains approximately constant, that is, the larger the phase bandwidth is, the better. From the constraint point of view, the space-time code has better performance in the flat fading channel, and the space-frequency code has better performance in the fast fading channel. In the actual application process, since the transmitter can not predict the channel state information, for this reason, the advantages of space-time code and space-frequency code can be integrated, and the STFC (empty-frequency code) scheme is proposed, in the spatial domain, time domain and frequency. The domain is jointly considered to achieve the maximum diversity gain under the multi-antenna fading channel.

 Based on the above-mentioned space-time/space-frequency/space time-frequency/spatial multiplexing coding processing technology, the structure of the transmitter and receiver applied in the wireless communication system in the prior art is as shown in FIG. 6 to FIG. Transmitters that transmit signals need to transmit at different frequencies to avoid co-channel interference.

 In the peak-slot system, since frequency resources are limited, frequency reuse is an effective means to improve frequency utilization. In a frequency-multiplexed cellular system, neighboring intra-frequency BSs (base stations) are covered by a family of cells of different frequencies, and N is used to indicate the number of frequency-multiplexed cells (i.e., cells using different frequencies). Suppose the system has K frequency points. In the frequency reuse group, each cell is divided into J frequency points (J<K), then

 K=JN=constant.

If the frequency reuse group is repeated M times in a certain area, the system capacity C of the area is - C=MK 0

 The system capacity C is proportional to M, and M is inversely proportional to N. If the N minimum is optimized during network planning, the peak system capacity is the largest.

 The frequency reuse rate q is defined as: q=D/R= ( 3N) 1/2;

 Where D is the frequency reuse distance, that is, the distance between adjacent intra-frequency base stations; R is the cell radius.

 It can be seen that the cellular system capacity is determined by the frequency reuse rate q.

 Frequency reuse inevitably causes mutual interference, that is, co-channel interference. The closer the distance D between adjacent base stations is, the smaller the frequency reuse rate q is. The larger the capacity of the cellular system is, the higher the frequency utilization is, but the larger the same frequency interference. The same-frequency interference mainly has 4 modes of interference, as shown in Figure 2 to Figure 5. Wherein, BS is a base station, SS is a subscriber station; TX represents a transmitting module, and RX represents a receiving module; and it is assumed that SS1 belongs to BS1 and SS2 belongs to BS2.

 The amount of interference power depends on the effective transmit power, multiplexing distance, and path loss. In existing cellular systems, complex power control techniques are typically employed to reduce co-channel interference. Therefore, the prior art requires complex network planning and requires complex power control techniques.

Summary of the invention

 It is an object of the present invention to provide a receiver and a wireless communication system that reduce the frequency reuse rate, thereby effectively reducing co-channel interference in a wireless communication system and simplifying the network planning scheme.

 The object of the invention is achieved by the following technical solutions:

 The invention provides a receiver for reducing frequency reuse rate, comprising:

 a set of receiving antennas: for receiving signals of each channel;

Signal receiving processing unit: respectively for processing each received signal; Interference suppression and cancellation unit: Used to suppress and cancel the interference between the received signals.

 The interference suppression and cancellation unit includes:

 A set of interference suppression and cancellation subunits: including the same interference suppression and cancellation subunits as the number of received signals, and respectively used to process each signal to obtain mutually independent received signals, the respective interference suppression And the offset subunits are sequentially connected in series, and the number of input signal paths thereof is sequentially reduced by one signal obtained by the previous processing to obtain the received signal; or

 An interference suppression and cancellation subunit: is used to process each received signal and directly output an effective signal.

 The receiver for reducing the frequency reuse rate further includes a space-time/space-frequency/space time-frequency/spatial multiplexing decoding unit corresponding to the transmitter end: for performing space-time/space-frequency/empty on the received signal Frequency/spatial multiplexing decoding processing.

 The signal receiving and processing unit includes:

 Demodulator: used to demodulate the received signal;

 De-mapping processing module: used for de-mapping processing of the demodulated signal;

 Channel decoding processing module: used for channel decoding processing on the demapped signal.

 The interference suppression and cancellation unit is connected to the demodulator, the demapping processing module, the channel decoding processing module, or the signal output side of the space/space/space time/space multiplexing decoding unit, and the corresponding The processed signal is subjected to interference suppression and cancellation processing.

 The receiver further includes a signal selection unit for selecting a signal from the received and correspondingly processed signals as the effective reception signal.

 The interference suppression and cancellation unit establishes settings based on maximum likelihood ML decoding, linear algorithm decoding, or nonlinear algorithm decoding.

 The present invention also provides a wireless communication system for reducing frequency reuse rate, comprising a transmitter and the receiver for reducing frequency reuse rate, wherein the transmitter passes the channel coding, symbol mapping and modulation processing signals through the transmitting antenna Transmit, the receiver receives the signal transmitted by the transmitter, and performs channel decoding, symbol demapping, demodulation, and interference suppression and cancellation processing on the signal to obtain a received signal.

 The transmitter includes at least two, and the receiver performs interference suppression and cancellation processing on at least two received signals.

 Each of the transmitters includes a bit-level based single coding unit transmitter and/or a symbol level based single coding unit transmitter, and the receiver side structure is provided corresponding to each transmitter structure.

The receiver includes - a bit-level based simple interference suppression receiver or a multi-decoding unit interference suppression receiver, simple symbol level based Interference suppression receiver or multi-decoding unit interference suppression receiver, bit-level mixing, symbol-level mixing, and bit-level and symbol-level mixing based multi-decoding unit interference suppression receiver.

 The wireless communication system for reducing frequency reuse rate, including a base station and a subscriber station, and

 The base station transmitter uses a common transmitter or a single coding unit transmitter, and different base stations transmit simultaneously or time-sharing. The receiver adopts a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and the user station transmitter adopts Ordinary transmitter or single coding unit transmitter, the user station receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver;

 Or,

 The base station uses a common transmitter or a single coding unit transmitter, and different base stations transmit between the base stations. The receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and the user station transmitter uses a common transmitter. Or a single coding unit transmitter, the user station receiver using a normal receiver or a single decoding unit receiver;

 Or,

 The base station and the subscriber station transmitter adopt a common transmitter or a single coding unit transmitter, and the base station and the subscriber station receiver adopt a normal receiver or a single decoding unit receiver, and different base stations transmit and time-sharing time-sharing.

 The single coding unit transmitter includes:

 Signal transmission processing unit: used for channel coding, symbol mapping and modulation processing of signals;

 Space-time/space-frequency/space-time/space multiplexing coding unit: used for space-time/space-frequency/space-time/space complexion before channel coding, or channel coding, symbol mapping or modulation processing Processed with encoding.

 It can be seen from the technical solution provided by the present invention that the implementation of the present invention can effectively overcome various existing co-channel interferences, effectively shorten the multiplexing distance, reduce the frequency reuse rate, and increase the capacity of the cellular system. Even cells in the cellular system can use only the same frequency and do not require complex network planning and power control techniques.

 That is to say, the implementation of the present invention can multiply the spectrum utilization rate without increasing the bandwidth and the antenna transmission power, thereby increasing the capacity of the wireless communication system.

BRIEF DESCRIPTION OF THE DRAWINGS

 Figure 1 is a schematic diagram of BLAST;

 2 to FIG. 5 are schematic diagrams of four co-channel interference scenarios in the prior art;

 Figure 6 is a conventional transmitter in the prior art;

 Figure 7 is a conventional receiver in the prior art;

 8 to 11 are four single coding unit transmitters in the prior art;

 12 to 15 are four single decoding unit receivers in the prior art;

 16 is a source bit level simple interference suppression receiver provided by the present invention;

17 is a channel bit level simple interference suppression receiver provided by the present invention; 18 is a source symbol level simple interference suppression receiver provided by the present invention;

 FIG. 19 is a channel symbol level simple interference suppression receiver provided by the present invention; FIG.

 20 is another channel bit level simple interference suppression receiver provided by the present invention;

 21 is a source bit level multi-decoding unit interference suppression receiver provided by the present invention;

 22 is a channel bit level multi-decoding unit interference suppression receiver provided by the present invention;

 23 is a source symbol level multi-decoding unit interference suppression receiver provided by the present invention;

 24 is a channel symbol level multi-decoding unit interference suppression receiver provided by the present invention;

 25 is a channel bit level and source symbol level hybrid multi-decoding unit interference suppression receiver provided by the present invention; FIG. 26 is another source symbol level multi-decoding unit interference suppression receiver according to the present invention;

 Figure 27 is a schematic diagram of the structure of the interference suppression and cancellation unit 1;

 Figure 28 is a schematic structural view of the interference suppression and cancellation unit 2;

 29 is a schematic structural diagram of a wireless communication system provided by the present invention;

 Figure 30 is a schematic structural diagram of a wireless communication system provided by the present invention;

Figure 31 is a schematic structural view 3 of a wireless communication system provided by the present invention ;

 Figure 32 is a schematic structural diagram of a wireless communication system provided by the present invention;

 FIG. 33 is a schematic structural diagram of a wireless communication system provided by the present invention.

 Figure 34 is a schematic structural diagram of a transmitter of BS1 based on space time code;

 35 is a schematic structural diagram of a transmitter of BS2 based on space time code;

 36 is a schematic structural diagram of a receiver based on the space code SS1;

Figure 37 is a block diagram showing the structure of a receiver based on space-time coded SS2.

Mode for carrying out the invention

 The core of the invention is to use MIM0 and hybrid space technology (for example, a combination of layered spatial multiplexing code, space-time code, space-frequency code or space-time code) to overcome the four kinds of co-channel interference, effectively shortening the complex Use distance, reduce frequency reuse rate, increase frequency utilization, and increase cellular system capacity.

 The wireless communication system for reducing frequency reuse rate according to the present invention relates to a general transmitter, a normal receiver, a single coding unit transmitter, a single coding unit receiver, a simple interference suppression receiver, and a multi-decoding unit interference suppression receiver, below They will be explained separately.

 (1) The structure of the conventional transmitter is as shown in FIG. 6, and specifically includes:

 a signal transmission processing unit, configured to perform channel coding, symbol mapping, and modulation processing on the transmission signal, and send the transmission signal by using a transmission antenna;

(2) The structure of the conventional receiver is as shown in FIG. 7, and specifically includes: a signal receiving processing unit configured to perform channel decoding, symbol demapping, and demodulation processing on the received signal of the receiving antenna; (3) The structure of the single-code unit transmitter is as shown in FIG. 8 to FIG. 11, and specifically includes: a space-time/space-frequency/space time-frequency/spatial multiplexing coding unit, configured to perform space-time on the source signal. / space frequency / space frequency / spatial multiplexing coding, forming a Ti strip transmission branch;

 a signal transmission processing unit, configured to perform channel coding, symbol mapping, and modulation processing on the transmission signal, and transmit; according to the position where the coding helmet is placed, there may be a single-code unit transmitter based on the bit level, as shown in FIG. 8 and FIG. As shown, a single-element unit transmitter based on symbol level, as shown in Figures 10 and 11; the minimum unit of coding of the bit-level encoder is a bit, and the minimum unit of coding of the symbol-level encoder is a symbol, for example, in Figure 10 The coded minimum unit may be a QAM symbol mapped symbol; the coded minimum unit in FIG. 11 may be an OFDM modulated OFDM symbol.

 For different transmission branches, channel coding mode, symbol mapping mode and modulation mode (such as OFDM modulation, 0FDMA modulation or spread spectrum modulation) of the same mode or different modes may be adopted;

 (4) The single decoding unit receiver, as shown in FIG. 12 to FIG. 15, specifically includes:

 a signal receiving and processing unit, configured to use a channel decoding mode, a symbol demapping method, and a demodulation mode, such as OFDM demodulation, 0FDMA demodulation, or spread spectrum demodulation, in the same mode or different modes for different receiving branches;

 Depending on where the decoder is placed, there may be a single-decoding unit receiver based on the bit level, as shown in Figures 12 and 13, a single-decoding unit receiver based on the symbol level, as shown in Figures 14 and 15; decoding of the bit-level decoder The minimum unit is a bit, and the decoding minimum unit of the symbol level decoder is a symbol. For example, the decoding minimum unit in FIG. 14 may be a symbol before demapping by QAM symbol; the minimum coding unit in FIG. 15 may be before OFDM demodulation 0FDM symbol.

 The above transmitters and receivers are transmitters and receivers of the prior art.

 (5) For a simple interference suppression receiver, the receiver is a receiver provided by the present invention, as shown in FIG. 16 to FIG.

 The signal receiving and processing unit corresponds to Rq receiving antennas (ie, a group of receiving antennas), receives different tributary signals, is assumed to be q-channel signals, and uses channel decoding mode, symbol demapping method and solution in the same mode or different modes. Tuning mode, such as 0FDM demodulation, 0FDMA demodulation or spread spectrum demodulation;

 The interference suppression and cancellation unit performs joint interference suppression and cancellation on the q decoding branches output by the signal receiving processing unit, and obtains the received signal after the q-channel interference suppression and cancellation, or obtains the received signal after the single-channel interference suppression and cancellation, As shown in Figure 20.

 Depending on the interference suppression and the location of the cancellation unit, there may be a simple interference suppression receiver based on the bit level, as shown in Fig. 16, Fig. 17, or Fig. 20, a simple interference suppression receiver based on the symbol level, as shown in Fig. 18 or Fig. 19.

a signal selection unit, configured to, after being processed by each unit of the receiver, if a q-channel interference suppression and a canceled received signal are obtained, selecting a signal from the q-channel received signal as a useful received signal, the specific selection The method is not limited in the present invention; if a single channel interference suppression and cancellation received signal is obtained, the signal selection unit is not required. (6) For a multi-decoding unit interference suppression receiver, the receiver is a receiver provided by the present invention, as shown in FIG. 21 to FIG.

 The signal receiving and processing unit has 13⁄4=^1 +~+3⁄4 +~+13⁄4 receiving antennas, receives different tributary signals, and adopts channel decoding mode, symbol demapping mode and demodulation mode of the same mode or different modes, for example OFDM demodulation, 0FDMA demodulation or spread spectrum demodulation;

 Corresponding to the transmitter side, there are space-time/space-frequency/space time-frequency/spatial multiplexing decoding units, and specifically, there may be q space-time/space-frequency/space-time/space multiplexing decoding units, and each decoding unit corresponds to , ···, Ri, ···,! 3⁄4 receiving antennas, forming q decoding branches; may be all trellis decoding or packet decoding for all decoding branches, or a part of decoding branches using network The decoding is performed while the other part of the decoding receiving branch uses packet decoding; when decoding the received signal of the i-th decoding branch, the other decoding branch signals are regarded as interference signal processing. The receiver's space/space/space time-frequency decoder requires channel estimation for MIM0 (multiple input multiple output), MIS0 (multiple input single output) or SIM0 (single input multiple output).

 Depending on the location of the decoding unit, there may be a bit-level-based multi-decoding unit interference suppression receiver, as shown in FIG. 21 or FIG. 22, a symbol-level multi-decoding unit interference suppression receiver, as shown in FIG. 23, FIG. 24 or FIG. 26, multi-decoding unit interference suppression reception based on source bit level and channel bit level mixing, based on source symbol level and channel symbol level mixing, and based on bit level (source or signal) and symbol level (source or signal) mixing , as shown in FIG. 25; the minimum decoding unit of the bit-level decoder is a bit, and the minimum decoding unit of the symbol-level decoder is a symbol. For example, the decoding minimum unit in FIG. 23 may be a symbol before demapping by QAM symbols; The medium coding minimum unit may be an OFDM symbol before OFDM demodulation.

 The interference suppression and cancellation unit is located after the space-time/space-frequency/space time-frequency/spatial multiplexing decoding unit, and is not necessarily followed by the q-block decoding branch jointly performing interference suppression and cancellation to obtain q-channel interference suppression and cancellation. After receiving the signal, or receiving the single channel interference suppression and cancellation of the received signal, as shown in Figure 26.

 a signal selection unit, configured to, after being processed by each unit of the receiver, if a q-channel interference suppression and a canceled received signal are obtained, selecting a signal from the q-channel received signal as a useful received signal, the specific selection The method is not limited in the present invention; if a single channel interference suppression and cancellation received signal is obtained, the signal selection unit is not required.

For the interference suppression and cancellation unit, in theory, ML (Maximum Likelihood) coding can be used to obtain the maximum spatial diversity (R), but the decoding complexity is large. Suboptimal algorithms can also be used: including linear algorithms such as zero-forcing (ZF) algorithms and minimum mean square error (awake SE) algorithms, and nonlinear algorithms such as SUC (Successive Cancellation). 0SUC (Ordered Successive Cancellation, another successive cancellation algorithm), namely ZF V-BLAST (Forced Zero Labs layered space-time structure), and so on. Among them, the linear algorithm has low decoding complexity, but because the useful information in the received signal is not fully utilized, the available diversity is only Ri-Ti+1, which is much lower than the method ML method, and the space-time characteristic is poor (although MMSE Performance is better than ZF). The characteristics of nonlinear methods are not as good as ML methods, but they The decoding complexity is much lower than the ML method, which is a good compromise between performance and complexity. In the nonlinear method, the performance of SUC is only slightly better than the linear method, while 0SUC is far superior to the linear method.

Suppose there is a q-way source, ···, , where the effective source is, that is, the target signal that the receiver really wants to receive. Then the interference suppression and cancellation thousand structural unit may be employed in the structure shown in FIG. 27, the interference suppression and cancellation unit has q input r ,, ···, r q, respectively, from the reception antenna 1, ... , q, then the interference suppression and cancellation unit is composed of q layer interference suppression and cancellation subunits; wherein, the layer 1 interference suppression and cancellation subunit is responsible for solving the source x by the q input 1Ί,..., , estimation of the received antenna signal q of q receiving antennas receiving a contribution l, ~, q is the received signal subtracted from the residual signal as the second layer 2 subunit interference suppression and cancellation. Of 2,.. Q interference suppression layer one thousand and one thousand x offset estimation signal and canceling interference suppression processing sub-units, the finally obtained information source Xl, ..., subunit 1 ... repeat the first layer, and then by the The signal selection unit selects the target signal.

 The present invention can also adopt another interference suppression and cancellation unit structure as shown in Fig. 28, and the interference suppression and cancellation unit has q input ...,! From the receiving antennas l, ~, q, respectively, the interference suppression and cancellation unit consists of only one layer of interference suppression and cancellation subunits; the first layer interference suppression and cancellation subunit is responsible for input by q: Π, · · ·, ^ In the direct selection, the target estimation signal i for the effective source is solved. The structure interference suppression and cancellation unit only has a single receiving processing branch, which avoids the need for a subsequent receiving processing branch of the q-path after the previous structural interference suppression and cancellation unit, and does not need to set the signal after the interference suppression and cancellation unit Select the unit. The following is an example of the application of the above various transmitters and receivers, especially the simple interference suppression receiver and the multi-decoding unit interference suppression receiver in the wireless communication system, i.e., the base station and the subscriber station system. The first implementation is shown in Figure 29 and Figure 30 - this scheme is applicable to TDD and FDD modes; for TDD mode, the assumption of synchronization is sent based on each mode network.

 The base station transmitter adopts a common transmitter as shown in FIG. 6 or a single coding unit transmitter shown in FIG. 8 to FIG. 11, and the base station receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver; The transmitter employs a conventional transmitter as shown in FIG. 6 or a single coding unit transmitter of FIGS. 8 to 11, and the subscriber station receiver employs a simple interference suppression receiver or a multi-decoding unit interference suppression receiver. Taking TDD as an example, referring to FIG. 29 and FIG. 30, there is no case of FIG. 29 under FDD; wherein, in each drawing, t0, tl, tr, tk, and tk+1 represent different moments; TX represents a transmitting module, RX denotes a receiving module; BS is a base station, SS is a subscriber station, and it is assumed that SS1 belongs to BS1, SS2 belongs to BS2; DL is a downlink frame, and UL is an uplink frame; FIG. 29 is a system for overcoming the interference shown in FIG. 2 and FIG. Schematic, FIG. 30 is a schematic diagram of a system that overcomes the disturbances shown in FIGS. 4 and 5. The second implementation scheme is shown in Figure 31 and Figure 32. This scheme is based on the assumption that each mode network sends synchronization, and is applicable to the TDD mode.

The base station transmitter adopts a normal transmitter as shown in FIG. 6 or a single coding unit transmitter shown in FIGS. 8 to 11, and the base station The receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and different base stations transmit time-sharing; the subscriber station transmitter uses the ordinary transmitter shown in FIG. 6 or shown in FIG. 8 to FIG. A single coding unit transmitter, and the subscriber station receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver.

 Referring to Figures 31 and 32: Figure 31 is a schematic diagram of a system that overcomes the interference shown in Figures 2 and 3, and Figure 32 is a schematic diagram of a system that overcomes the interference shown in Figures 4 and 5. The third implementation is shown in Figure 33:

 This scheme is applicable to TDD and FDD modes; for TDD mode, it is based on the assumption that each mode network sends and receives synchronization.

 The base station adopts the ordinary transmitter shown in FIG. 6 or the single coding unit transmitter shown in FIG. 8 to FIG. 11, and the base station receiver adopts a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and different base stations are time-sharing. Transmitting; the subscriber station is received by a conventional transmitter as shown in FIG. 6 or a single-encoding unit transmitter shown in FIGS. 8 to 11 and a conventional receiver shown in FIG. 7 or a single decoding unit shown in FIGS. 12 to 15. machine.

 Taking TDD as an example, see Figure 24, a schematic diagram of the system to overcome the interference shown in Figures 2 and 3. Since the transmission and reception of each mode network is synchronized, the interference shown in Fig. 4 and Fig. 5 will not be introduced. The specific implementation of the present invention will be described below by taking a space-time code as an example. The corresponding implementations are shown in Figures 34, 35, 36 and 37, and specifically include:

 Space time codes are primarily directed to flat fading channels, while in actual high speed data transmission systems the channel characteristics are typically frequency selective fading. OFDM (Orthogonal Frequency Division Multiplexing) techniques can divide a frequency selective fading channel into a plurality of parallel correlated flat fading channels, thus exhibiting non-frequency selective fading on each carrier. One embodiment of the present invention uses a combination of space time code and orthogonal frequency division multiplexing techniques for OFDM systems.

 Assuming the adjacent intra-frequency base stations BS1 and BS2, the subscriber station SSI belongs to BS1, and SS1 is interfered by BS2. An OFDM system based on dual-antenna transmit diversity, single-antenna receive simple space-time code techniques, as shown in Figures 16 and 18. There are 2 transmitting antennas at the transmitting end of each base station, and the distance between them is at least λ /2 (λ is the wavelength), that is, the process of transmitting signals in different paths should be approximated as independent attenuation processes, and received at the subscriber station. There are 2 receiving antennas on the side. The space-time decoder of this scheme requires multi-input and multi-output (MIM0) channel estimation.

 Source 1 (or source 2) is channel coded/symbol mapped and then symbol-level simple space-time coded. The two outputs are then OFDM modulated, and finally transmit antennas 1 and 2 (transmit antennas or 3 and 4) send.

The base station 1 space-time encoder inputs a pair of symbols (&, &), that is, at time ft, the symbols & and & are transmitted from antenna 1 and antenna 2, respectively; at time 7, the symbols and (*) are transmitted from antenna 1 and antenna 2, respectively. . The base station 2 space-time encoder inputs the paired symbols is, X2, that is, at the time ft symbol and from the antenna 1 and the antenna 2, respectively; at the time symbol (- and (X*) are transmitted from the antenna 3 and the antenna 4, respectively. *) indicates complex conjugate. This ensures that the symbol to be transmitted has an orthogonal space-time structure, which constitutes full time domain diversity. The received signals of the two antennas of the user station 1 receiver are respectively demodulated by OFDM, and the two OFDM signals output are respectively decoded by symbol-level simple space-time decoding, and then the interference suppression and cancellation unit outputs the pure BS1 signal and the pure BS2 signal. Then, channel decoding/symbol de-mapping is performed separately, and finally the BS1 signal is selected. The structure of the receiver of the subscriber station 2 is more compact. The two received signals are respectively demodulated by OFDM, and the two OFDM signals output are respectively decoded by the symbol level simple space-time, and then the pure BS2 signal is directly output through the interference suppression and cancellation unit. Then do channel decoding/symbol de-mapping to get the BS2 signal.

 At each receive branch, the space-time decoder performs a space-time linear combination of the received signals as follows to obtain a Ti XRi (Ti = 2, Ri = l) order diversity in this case:

Wherein, the channel coefficient from the transmitting antenna j to the receiving antenna i is the result of channel estimation of the multiple input multiple output (MIM0); ) is an additive white Gaussian noise (AWGN) satisfying a normal distribution; coefficient (2/) 1 2 is used to normalize the transmit power; to be the number of transmit antennas, in this example equal to the sum of the two base station transmit antennas ; n = 1 or 2. In summary, the implementation of the present invention can overcome the same-frequency interference shown in FIG. 2 to FIG. 5, effectively shorten the multiplexing distance, reduce the frequency reuse rate, and increase the capacity of the peak-slot system. Even cells in a cellular system can use only the same frequency without complex network planning and power control techniques.

 The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatives are intended to be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Rights request
A receiver for reducing a frequency reuse rate, comprising: - a set of receiving antennas: for receiving signals of respective paths;
 Signal receiving processing unit: respectively for processing each received signal;
 Interference suppression and cancellation unit: Used to suppress and cancel the interference between the received signals.
 2. The receiver for reducing frequency reuse rate according to claim 1, wherein the interference suppression and cancellation unit comprises:
 A set of interference suppression and cancellation sub-units: including interference suppression and cancellation sub-units having the same number of received signal paths, and respectively for processing each of the signals to obtain mutually independent received signals, the respective interference suppression and The offset subunits are sequentially connected in series, and the number of input signal paths thereof is sequentially reduced by one signal obtained by the previous processing to obtain the received signal; or
 An interference suppression and cancellation subunit: is used to process each received signal and directly output an effective signal.
 ·
The receiver for reducing frequency reuse rate according to claim 1, wherein the receiver further comprises a space/space frequency/space time frequency/space multiplexing decoding unit corresponding to the transmitter end. : Used to perform space-time/space-frequency/space time-frequency/spatial multiplexing decoding processing on the received signal.
 The receiver for reducing the frequency reuse rate according to claim 1, 2 or 3, wherein the signal receiving processing unit comprises: a demodulator: configured to perform demodulation processing on the received signal;
 De-mapping processing module: used for de-mapping processing of the demodulated signal;
 Channel decoding processing module: used for channel decoding processing on the demapped signal.
 The receiver for reducing frequency reuse rate according to claim 4, wherein the interference suppression and cancellation unit is connected to a demodulator, a demapping processing module, a channel decoding processing module, or The signal output side of the time/space frequency/space time/space multiplexing decoding unit performs interference suppression and cancellation processing on the corresponding processed signal.
 The receiver for reducing the frequency reuse rate according to claim 5, wherein the receiver further comprises: a signal selection unit: configured to select a signal from the received and processed signals as a signal Receive signals efficiently.
 7. The receiver for reducing frequency reuse rate according to claim 5, wherein said interference suppression and cancellation unit is based on maximum likelihood ML decoding, linear algorithm decoding or nonlinear algorithm decoding. Establish settings.
8. A wireless communication system for reducing frequency reuse rate, comprising: a transmitter and said reduced frequency a receiver of multiplexing rate, the transmitter transmits a signal subjected to channel coding, symbol mapping and modulation processing through a transmitting antenna, the receiver receives a signal transmitted by the transmitter, and performs channel decoding and symbol demapping on the signal , demodulation and interference suppression and cancellation processing to obtain the received signal.
 9. The wireless communication system for reducing frequency reuse rate according to claim 8, wherein said transmitter comprises at least two, said receiver performing interference suppression and cancellation on at least two received signals. deal with.
 10. A radio communication system for reducing frequency reuse rate according to claim 8 or 9, wherein said respective transmitters comprise bit-level based single coding unit transmitters and/or symbol level based single coding. a unit transmitter, and the receiver side structure is set corresponding to each transmitter structure.
 The wireless communication system for reducing the frequency reuse rate according to claim 10, wherein the receiver comprises:
 Bit-level based simple interference suppression receiver or multiple decoding unit interference suppression receiver, symbol level simple interference suppression receiver or multiple decoding unit interference suppression receiver, bit-level mixing, symbol-level mixing and bit-level based Symbol level mixed multiple decoding unit interference suppression receiver.
 The radio communication system for reducing frequency reuse rate according to claim 8 or 9, wherein the system comprises a base station and a subscriber station, and
 The base station transmitter adopts a common transmitter or a single coding unit transmitter, and different base stations transmit simultaneously or time-division. The receiver adopts a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and the user station transmitter adopts a common transmitter. Or a single coding unit transmitter, the subscriber station receiver employing a simple interference suppression receiver or a multi-decoding unit interference suppression receiver;
 Or,
 The base station uses a common transmitter or a single coding unit transmitter, and different base stations transmit time-sharing. The receiver uses a simple interference suppression receiver or a multi-decoding unit interference suppression receiver, and the user station transmitter uses a common transmitter. Or a single coding unit transmitter, the subscriber station receiver uses a normal receiver or a single decoding unit receiver;
 Or,
 The base station and the subscriber station transmitter adopt a common transmitter or a single coding unit transmitter, and the base station and the subscriber station receiver adopt a normal receiver or a single decoding unit receiver, and different base stations transmit and time-sharing time-sharing.
 The wireless communication system for reducing frequency reuse rate according to claim 12, wherein the single coding unit transmitter comprises:
 Signal transmission processing unit: used for channel coding, symbol mapping and modulation processing of signals;
 Space-time/space-frequency/space-time/space multiplexing coding unit: used for space-time/space-frequency/space-time/space complexion before channel coding, or channel coding, symbol mapping or modulation processing Processed with encoding.
PCT/CN2006/001340 2005-07-05 2006-06-15 Receiver and radio communication system for reducing the rate of frequency multiplex WO2007003096A1 (en)

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