WO2009079841A1

WO2009079841A1 - Signal forwarding method and apparatus serving in relay station of a plurality of network apparatuses

Info

Publication number: WO2009079841A1
Application number: PCT/CN2007/003682
Authority: WO
Inventors: Yang Song; Jimin Liu; Wei Ni; Xiaolong Zhu
Original assignee: Alcatel Shanghai Bell Company, Ltd.; Alcatel Lucent
Priority date: 2007-12-19
Filing date: 2007-12-19
Publication date: 2009-07-02
Also published as: CN101874367B; CN101874367A

Abstract

A signal forwarding method in a relay station in a wireless communication network comprises the following steps: a) judging whether the time-frequency resources which are occupied in the communication between a plurality of network devices and the present relay station, are totally or partially same (S11); b) according to the preset rules and the channel related information of a plurality of channels between the plurality of network devices and the present relay station, carrying on the process on the communication signals between the plurality of network devices and the present relay station (S12). The present invention could reduce the same-frequency interference between multi-cells, promote the system capability, and enlarge the cell coverage. When using a plurality of relay stations, the present invention could improve the signal quality.

Description

Serving multiple network devices

Method and device for signal forwarding in relay station

The present invention relates to a wireless communication relay network, and more particularly to a method and apparatus for signal forwarding in a relay station that simultaneously serves a plurality of network devices in a wireless communication relay network. Background technique

When the mobile station is located in an area with severe inter-cell interference, such as a cell edge area, co-channel interference (or co-channel interference) from neighboring cells severely reduces the communication quality between the mobile station and the base station, and further limits the entire system. Coverage and throughput.

The more conventional methods for suppressing inter-cell interference in the prior art include technologies such as Fractional Frequency Reuse (FFR) or Macro Diversity (MD). Taking the OFDM/OFDMA system as an example, the subcarrier reuse scheme of partial frequency reuse is shown in FIG. 1. The mobile station located in the central area of the cell can use all frequency resources, and the mobile station located in the cell edge area can only use the available frequency. A part of the resource set, as shown in FIG. 1, assumes that F1+F2+F3 is a set of available frequency resources, and Fl, F2, and F3 are frequency resource sets that do not overlap each other, and mobile stations located in the central area of each cell can use For all frequency resources, the mobile station located in the edge area of the first cell C1 uses only the frequency resources in the F1 set, and the mobile station located in the edge area of the second cell C2 uses only the frequency resources in the F2 set, and is located in the edge area of the third cell C3. The mobile station only uses the frequency resources in the F3 set. In this way, by allocating different frequency resources to mobile stations located in the edge areas of adjacent cells, the co-channel interference from neighboring cells received by the cell edge users is effectively reduced. However, since the mobile station located in the cell edge area can only use a part of the available frequency resources, the capacity of the cell edge area is limited.

The scheme of macro diversity is as follows: In a cell edge region, multiple base stations serve a mobile station on the same time-frequency resource, and the method can also effectively reduce co-channel interference between cells. However, due to the need for coordination between multiple base stations, and because multiple base stations can only serve one mobile station instead of multiple mobile stations on the same time-frequency resource, the whole system is limited. Summary of the invention

In view of the above disadvantages of the prior art scheme for suppressing inter-cell interference, the present invention proposes a new scheme for suppressing inter-cell interference. One or more relay stations are placed in an area with severe intra-frequency interference (such as a cell edge area), and the one or more relay stations receive different source network devices (base stations, relay stations, or mobile stations) on the same time-frequency resource. Signals or send different signals to different target network devices (mobile stations, 'relay stations or base stations;).

According to a first aspect of the present invention, there is provided a method for signal forwarding in a relay station of a wireless communication network, wherein the relay station comprises a plurality of receiving and transmitting antennas, characterized in that the method comprises the following steps: a. Determining whether a plurality of network devices occupy part or all of the same time-frequency resource when communicating with the relay station; b. if the plurality of network devices communicate with the relay station to occupy part or all of the same time-frequency resource, then the relay station is The communication signals between the plurality of network devices and the relay station are processed based on predetermined rules and based on channel-related information of the plurality of network devices and the plurality of channels of the relay station on part or all of the same time-frequency resources.

According to a second aspect of the present invention, there is provided a forwarding device for signal forwarding in a relay station of a wireless communication network, wherein the relay station comprises a plurality of receiving and transmitting antennas, characterized in that the forwarding device comprises a determining device And processing equipment. The determining device determines whether the plurality of network devices occupy part or all of the same time-frequency resource when communicating with the relay station; if the plurality of network devices occupies part or all of the same time-frequency resource when communicating with the relay station, the processing device is The part or all of the same time-frequency resources are processed on the communication signal between the plurality of network devices and the relay station based on a predetermined rule.

In the present invention, since the relay station can communicate with multiple network devices on the same time-frequency resource, not only can the same-frequency interference between multiple cells be effectively reduced, but also the system supports The number of users held increases the system capacity, and also has the advantage of expanding the coverage of the cell. Since each base station independently allocates time-frequency resources to its own relay stations and mobile stations, coordination between base stations is not required. The solution of the invention is also transparent to the mobile station. If multiple relay stations are used, the signal quality of the received or transmitted signal can be further improved. In addition, the present invention is applicable not only to a case where a plurality of base stations share one or more relay stations to mitigate inter-cell interference, but also to a case where one base station administers one or more relay stations, and the one or more relay stations are at the same time The frequency resource serves multiple user terminals to increase system capacity while expanding system coverage. DRAWINGS

Other features, objects, and advantages of the invention will become apparent from the Detailed Description of Description In the figures, the same reference numerals are used for the same or similar.

1 is a schematic diagram of partial frequency reuse in a wireless communication network in the prior art; FIG. 2 is a schematic diagram of a network topology structure of a wireless communication network according to an embodiment of the present invention;

3 is a schematic diagram of another network topology structure of a wireless communication network according to an embodiment of the present invention;

4 is a schematic diagram of still another network topology structure of a wireless communication network according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of still another network topology structure of a wireless communication network according to an embodiment of the present invention; FIG.

6 is a flow chart of a method for signal forwarding in a relay station of a wireless communication network, in accordance with an embodiment of the present invention;

Figure 7 is a block diagram showing the structure of a forwarding device for signal forwarding in a relay station of a wireless communication network in accordance with an embodiment of the present invention. detailed description

2 shows a network topology structure according to a specific selling manner of the present invention. Figure. 2 includes a base station B2, a mobile station M3 under the jurisdiction of the base station B2, a base station B2', a mobile station M3 under the jurisdiction of the base station B2', and a relay station R1 located at the edge of the cell under the jurisdiction of the base station B2 and the base station B2. The base station B2 and the base station B2 share a relay station R1.

The following line transmission is taken as an example to describe a specific embodiment of the present invention in detail.

Base station B2 and base station B2 independently allocate time-frequency resources to respective mobile stations and relay stations under their jurisdiction (for the sake of brevity, other mobile stations and relay stations are not shown in Fig. 2).

The relay station R1 knows which time-frequency resources it is to be based on, according to the time-frequency resource mapping signaling from the base station B2, for example, the downlink mapping information (DL-MAP) located in the front of the physical frame in the WiMAX, including the time-frequency resource mapping information. The signal transmitted from the base station B2 to the mobile station M3 is received and the time-frequency resources are forwarded to the mobile station M3. Similarly, the relay station R1 knows according to the time-frequency resource mapping signaling from the base station B2, for example, the time-frequency resource mapping information in the downlink mapping information (DL-MAP) located in the front of the physical frame in WiMAX. The frequency resource receives the signal from the base station B2, transmits it to the mobile station M3, and on which time-frequency resources the signal is forwarded to the mobile station M3.

The process by which the relay station R1 receives different signals from the base station B2 and the base station B2 is as follows:

It is assumed that the time-frequency resources used for signal transmission between the base station B2 and the relay station R1 and the base station B2 and the relay station R1 have some same time-frequency resources and some different time-frequency resources.

On those different time-frequency resources, the relay station R 1 directly detects the signals from the base station B2 and the base station B2 on the respective time-frequency resources. This is similar to the existing processing of a relay station serving only one base station, and the present invention will not be described in detail.

On those same time-frequency resources, the relay station R1 separates the received mixed signals from the base station B2 and the base station B2 by using a detection and decoding method of multiple-input multiple-output (MIMO) technology. To obtain signals from base station B2 and base station B2, respectively. There are many methods for detecting and decoding MIMO. The following is an example of linear forcing (ZF, Zero Forcing) detection to dock the relay station R1. The process of detecting and decoding the received mixed signal (that is, separating the signals from the base station B2 and the base station B2) will be described in detail. It is assumed that the relay station has two receiving antennas, and the base station B2 and the base station B2 each have one transmitting antenna.

a channel transmission matrix between the base station B2, the base station B2, and the relay station R1, wherein hu and h ₂₁ are channel transmission coefficients between the antennas BA1 of the base station B2 and the two antennas RA1 and RA2 of the relay station R1, respectively; h ₁₂ , h ₂₂ is the channel transmission coefficient between the antenna of the base station B2' to the two antennas RA1, RA2 of the relay station R1; the entire channel transmission matrix from the base station B2 and the base station B2 to the relay station R1 is represented as

^H BR = [ ^H BRI The signal received in relay station R1 can be written as follows

expression

Where yl and y2 are respectively received by the two antennas RA1 and RA2 on the relay station R1; _s = , where Si is the signal sent by the base station B2 to the mobile station M3, and s ₂ is the base station B2, and is sent to the mobile station M3, The signal of " = for the noise term multiplied by the formula ( 1 ) gives the following expression:

HB~ _R y = H- _R ^l H _BR s + H" = Is + H~ ( 2 ) Since 11 is a noise term, it is generally estimated in advance; H is a channel transmission coefficient matrix, which can be estimated in advance by channel estimation. The result of £^ is the identity matrix / ; Therefore, the estimated value of the transmitted signal s ₂ can be obtained according to the formula (2), that is, ₈₁ and s _{2 are} solved.

The relay station R 1 sends different signals to the mobile station M3 and the mobile station M3, as follows:

The relay station R1 transmits the detected and decoded signals to the mobile station M3 and the mobile station M3 according to the time-frequency resources allocated to the respective mobile stations served by the base station B2 and the base station B2. The time-frequency resources used may have some of the same time-frequency resources, or some may not The same time-frequency resources.

For the case where the relay station R1 separately transmits signals to the mobile station M3 and the mobile station M3 using different time-frequency resources, the relay station R1 transmits signals to the mobile station M3 on the different time-frequency resources allocated by the base station B2 and the base station B2, respectively. And mobile station M3'. This is similar to the prior art, and the present invention will not be described in detail.

In the case where the signal transmission of the relay station R1 to the mobile station M3 and the signal transmission of the relay station R1 to the mobile station M3 use the same time-frequency resource, the relay station R1 needs to use the multi-user spatial division multiple access (SDMA) precoding technique to transmit the signal. _Sl and s ₂ are precoded to reduce or even eliminate interference between multiple users. At this time, a multi-user MIMO (MU-MIMO, Multi-User MIMO) system is formed between the relay station R1 and the mobile station M3 and the mobile station M3. . Multi-user MIMO precoding is an implementation technique for multi-user SDMA.

There are many methods for multi-user SDMA precoding. The following is a linear inverse channel forcing (Channel Inversion) precoding (inverse channel zero-forcing is a kind of zero-forcing SDMA precoding), for the relay station R1 The process of precoding the signals transmitted to the mobile station M3 and the mobile station M3 on the same time-frequency resource will be described in detail. Still, the relay station R1 has two transmitting antennas, a mobile station M3, and a mobile station M3, each having one receiving antenna as an example. Set "z _12], H ¾] channel transfer matrix are relay stations Rl to the mobile station M3 and the mobile station M3, where, m", m _12, respectively repeater R1 two antennas RA1 and RA2 to the mobile station M3 The channel transmission coefficient of the receiving antenna MA1; m ₂₁ and m ₂₂ are channel transmission coefficients of the receiving antennas of the two antennas RA1 and RA2 of the relay station R1 to the mobile station M3, respectively. The entire channel transmission matrix from the relay station R1 to the mobile station M3 and the mobile station M3 is expressed as:

It is a signal formed by precoding the signal to be transmitted to be transmitted to the mobile station M3 and the mobile station M3, and is precoded by the inverse channel method. The expression of X is as follows: L ”

Where a is the power normalization factor and w - H is the precoding matrix. At this time, the signal received by the mobile station M3 is:

n = aH _m ^- s + n ₃ = as, + n ₃ ( 5 ) Similarly, the mobile station M3 receives the signal as:

'a = aH _mi H,' , s + n, = s ₂ +n ( 6 ) where n ₃ and n ₄ are noise terms, and their estimated values can be determined in advance. As described above, the relay station R1 can calculate the precoding matrix and precode the signal to be transmitted by using the channel transmission matrix H of the relay station R1 to the mobile station M3 and the mobile station M3, which are obtained in advance, so that the receiving end, that is, the mobile station M3 can be made. And the mobile station M3 is capable of receiving signals transmitted to them separately, thereby avoiding interference between individual users.

It should be noted that when the relay station R 1 transmits signals to the mobile station M3 and the mobile station M3, it is necessary to form a physical frame transmission by using a multi-user SDMA precoded signal using the same time-frequency resource together with a signal using different time-frequency resources. .

The downlink signal transmission is described in detail above by taking the MIMO detection decoding of the zero-forcing method and the SDMA pre-coding of the inverse channel zero-forcing method as an example. One of ordinary skill in the art will appreciate that the uplink signal transmission is similar. The invention is not described in detail herein. In addition, the method of the present invention is not limited to the zero-forcing MIMO detection decoding and the channel reversal zero-precoding, and the relay station R1 receives spatial division multiplexing (SM, Spatial) from different source network devices on the same time-frequency resource. Multiplexing) After mixing signals, there are many methods for MIMO detection and decoding of the mixed signal, which are mainly divided into linear and nonlinear methods. Linear detection and decoding methods include the above-mentioned zero-forcing method (see Reference 1: Wolniansky). PW, Foschini GJ, Golden GD, et al. V-BLAST: an architecture for realizing very high data rates over the rich-scattering wireless channel. In ISSSE, Pisa, Italy, 1998. 295-300; Reference 2: BA Bjecke , JG Proakis. Multiple transmit and receive antenna diversity techniques for wireless communications. Proceedings of IEEE Adaptive Systems Signal Processing, Communications, Control Symp., Lake Louise, AB, Canada, October, 2000. 70-75), Minimum Mean Squared Error (MMSE, See Reference 2), and their various variants, simplifications; The code method includes further use of various interference cancellation (IC:, Interference Cancellation, see Reference 1) techniques, and maximum likelihood method (ML, Maximum Likelihood, for details). Document 3: G. Awater, A, van Zelst, R. van Nee. Reduced complexity space division multiplexing receivers. Proceedings of IEEE Vehicular Technology Conf., vol. 1, Tokyo, Japan, May, 2000. 11-15 ) Various simplified deformations, such as maximum likelihood detection based on QR decomposition and M algorithm; QRM-ML, QR decomposition and M-algorithm based ML, see Reference 4: H. Kawai, K. Higuchi, N Maeda, et al. Likelihood function for QRM-MLD suitable for soft-decision Turbo decoding and its performance for OFCDM MIMO multiplexing in multipath fading channel. IEICE Trans. Commun., E88-B(l), 2 005. 47-56) „In the case where the relay station R1 needs to send different signals to multiple different target network devices on the same time-frequency resource, there are various methods for SDMA pre-coding the signal, which are mainly divided into linear and non-linear. Linear two-class methods, linear precoding methods include the aforementioned inverse channel zero-forcing method (see Reference 5: Spencer Q. Η·, Peel CB, Swindlehurst AL, et al. An Introduction to the multi-user MIMO downlink. IEEE Communications Magazine, October 2004. 60-67), Minimum Mean Square Error Method (see Reference 5), Block Diagonalization (BD, Block Diagonalization, see Reference 6: Spencer QH, Swindlehurst AL, Haardt M. Zero-forcing methods for downlink spatial multiplexing in multiuser MIMO channels. IEEE Transactions on Signal Processing, vol. 52, No. 2, February, 2004. 461-471 ), beamforming method (BF, Beamforming, see references) 7: Liberti JC, Rappaport TS Smart Antenna in Wireless Communications - IS95 and 3rd Generation CDMA Applications. Mechanical Industry Press, 2002. ) or based on predetermined code calligraphy (See Reference 8: Philips. Comparison between MU-MIMO codebook-based channel reporting techniques for LTE downlink. Rl -062483, October 2006. 3GPP TGS RAN WG1 Meeting #46bis, Seoul ) etc., and their Various deformations, such as multi-user Eigenmode Transmission ( MET , Multi-user Eigenmode Transmission , see Reference 9 : Lucent Technologies. Downlink enhancements using additional antennas, full channel knowledge, and multiuser eigenmode transmission. Rl -061877, June, 2006. TSG-RAN WGl LTE, Cannes, France), Minimum Mean Square Error of Transceiver Iteration (TR-MMSE, see Reference 10: MT Ivrlac, RL Choi, RD Murch, JA Nossek. Effective user of long- Term transmit channel state information in multi-user MIMO communication systems. Proceedings of IEEE VTC03, October, 2003. 373-377. ) Method; nonlinear precoding method including DPC, Dirty Paper Coding, see Reference 5) 'and its variants, etc.

It should be noted that a specific embodiment of the present invention has been described in detail by taking a relay station of two base stations as an example. It should be understood by those skilled in the art that the present invention is not limited thereto. In the edge region of two neighboring cells shown in FIG. 2, multiple relay stations may be placed, thereby causing one or more target network devices (upstream refers to a base station or a next hop relay station, and downlink refers to a mobile station or a next hop) Relay station) can obtain RF gain or spatial multiplexing or diversity gain. As shown in Fig. 3, the functions of the reception detection decoding and precoding transmission processing performed by the plurality of relay stations are exactly the same as those of the relay station R1 shown in Fig. 2. The multiple relay stations can implement macro diversity, distributed spatial multiplexing or space-time coding (STC) for a mobile station they jointly serve on the basis of the function of the relay station of FIG. 1 to obtain RF gain. Or spatial multiplexing or diversity gain.

Here, the following line transmission is taken as an example to describe in detail the case where the two relay stations in the present invention implement Distributed Space-Time Block Coding (DSTBC).

The signal s ₂ i, s ₂₂ sent by the base station B2 to the mobile station M3 at two times ti, t ₂ at the time ti, t ₂ and the signal s ₂ i, s _{22 of the} mobile station M3 at the time t ₂ (of course, After the relay station R1 and the relay station R1, the relay arrives at the mobile station M3 and the mobile station M3, respectively. On those using the same time-frequency resources, according to the MIMO detection described above The 7" code 2 method, the relay station R1 and the relay station R1, can respectively solve the s _u and s _{21 of the} time, the s ₁₂ and s _{22 of the} time t ₂ .

The relay station R1 performs space-time block coding on the signals s ₁₂ and s _u sent to the mobile station M3, taking the Alamouti code as an example, that is, the Alamouti-encoded signal matrix to be transmitted 1: the signal to the mobile station M3' ₂₂ , s ₂₁ performs Alamouti encoding, that is, the Alamouti encoded signal matrix 2 to be transmitted is obtained:

Represents the conjugate of a complex number.

Similarly, the relay station R1 performs the same space time block coding as the relay station R1.

It is assumed that the relay station R1 transmits the first line to be transmitted in the to-be-transmitted signal matrices 1 and 2 [-4 and [-4 3⁄4], that is, transmits s _u and s ₂₁ at the time, and transmits - 4 and - 4 at time t ₂ . The relay station R1 transmits the second line to be transmitted in the to-be-transmitted signal matrices 1 and 2 [4 3⁄4] and 3⁄4], that is, at time t, the transmission of s ₁₂ and s ₂₂ , at t ₂ , the time of transmission and in order to make the mobile station M3 and mobile station M3 are capable of receiving signals respectively transmitted thereto, and relay station R1 needs to perform SDMA precoding for s _u , s ₂₁ which are transmitted at the time, and - 4, - 4 which are transmitted at time t ₂ , respectively. The relay station R1' needs to perform SDMA precoding for s ₁₂ and s ₂₂ transmitted at the time and 4 and 4 transmitted at time t ₂ respectively.

According to the formula (4), it is assumed that the precoding matrix in the relay station R1 is ^ = « , where H^ is the receiving antenna MA1 of the two transmitting antennas RA1, RA2 of the relay station R1 to the receiving antenna MA1 of the mobile station M3 and the mobile station M3, The channel transmission matrix between the two is the power normalization coefficient, and the signal transmitted at the time on the two antennas RA1 and RA2 of the relay station R1 is = at t ₂ , and the signal transmitted at the time is

, where _1⁄2 and _3⁄4 are respectively ^, moment antenna RA1

The transmitted signals on RA2, ₁ and _3⁄4 are respectively t ₂ , the transmitted signals on the antennas RA1, RA2. Similarly, precoding is performed in the relay station R1, and the precoding matrix of the relay station R1 is set.

, where H _fiW is the channel transmission matrix between the two transmitting antennas RA1, RA2' to the receiving antenna MA1 of the mobile station M3 and the receiving antenna 移动 of the mobile station M3, where ^ is the power normalization coefficient, Then two antennas of the relay station R1

RA1, and RA2, the signal sent at the time t ₂ ' is

The signals transmitted on the antennas RA1, A2', _x2 ' ₁ , and the signals transmitted on the time antennas RA1, RA2, respectively.

Due to the interaction of the precoding matrix and the channel transmission matrix (refer to equations (5), (6)), the mobile station M3 receives only the su and the relay station R1 transmitted by the relay station R1 at the time, and transmits the s ₁₂ at t _{2. At the} moment, only the -4 transmitted by the relay station R1 and the relay station R1 are transmitted, and the transmitted ^ is formed, thereby forming a complete Alamouti coded signal. Similarly, the mobile station M3 receives only the s ₂₁ and the relay station IU transmitted by the relay station R1 at the time, and the transmitted s ₂₂ , at time t ₂ , receives only the -4 transmitted by the relay station R1 and the relay station R1, and transmits the 3⁄4, thereby constituting Complete Alamouti encoded signal.

It should be noted that the present invention is not limited to the application scenario in which one or more relay stations are shared by two base stations as shown in FIG. 2 and FIG. 3, and a relay station having multiple antennas may be placed in one cell, and the relay station only has jurisdiction. The base station of the cell is under the jurisdiction, and the relay station can support multiple mobile stations on the same time-frequency resource, thereby increasing the system capacity while expanding the coverage, as shown in FIG. 4, during downlink transmission, between the base station B2 and the relay station R1. Forming a MIMO system, a downlink multi-user MIMO system is formed between the relay station R1 and the mobile station M3 and the mobile station M3; in the uplink transmission, the uplink multi-user MIMO system is formed between the mobile station M3 and the mobile station M3 and the relay station R1. A MIMO system is formed between the relay station R1 and the base station B2. By relaying via the relay station R1, the base station B2 can communicate with the mobile station M3 and the mobile station M3 on the same time-frequency resource. Thereby effectively increasing system capacity and coverage without sacrificing time-frequency resources. And, since the relay station R1, the mobile station M3 and the mobile station M3, and the relay station are employed The distance between R1 is relatively close, and the transmission power of the mobile station M3 and the mobile station M3 is also saved. In addition, the source network device or the target network device of the communication relayed via the relay station in the present invention is not limited to the base stations B2 and B2, or the mobile stations M3 and M3. As shown in FIG. 5, the source network device or the target network device may also be Another hop relay station R.

It should be noted further that the signal _Sl in the above formula, symbol ₈₂ generally level modulation signal (e.g., QAM, QPSK modulation symbols, etc.), in an OFDMA system, i.e. the signal level modulation symbol on a single subcarrier, when a A frequency resource may contain multiple such modulated signals. When receiving the signal from multiple source network devices, the relay station R1 needs the foregoing MIMO detection and decoding for each modulation symbol in the same time-frequency resource occupied; when the relay station R1 sends different signals to multiple target network devices, it is occupied. Each of the modulation symbols within the same time-frequency resource is subjected to the aforementioned multi-user SDMA precoding process. After the MIMO detection and decoding of the received mixed signal, the relay station R1 obtains each symbol level modulated signal, and can directly forward each symbol level modulated signal to the corresponding target network device by using the multi-user SDMA precoding technology; The symbol-level modulated signal can be further channel-decoded into bit-level data information to correct some erroneous bits that may exist. When transmitting, the bit information is channel-encoded, then symbol-modulated to obtain a symbol-level signal, and then The multi-user SDMA precoding technology is used to pre-code each symbol-level signal to be transmitted and convert it into a radio frequency signal and send it to the corresponding target network device.

It should be noted that the present invention has been described in detail with two adjacent cells as an example. Those skilled in the art should understand that the present invention is also applicable to N cells (N>=3). In the case of neighbors, at this time, the relay station R1 is jointly governed by N base stations. Generally, the number of receiving antennas of the relay station is greater than or equal to the number of data streams to be received, and the number of transmitting antennas is greater than or equal to the number of data streams to be transmitted. Another point to note is that since the transmitting and receiving signals of the relay station are time-sharing (such as time division duplex system, TDD) or frequency division (such as frequency division duplex system, FDD), the transmitting antenna and the receiving antenna can Share.

6 shows a flow diagram for signal forwarding in a relay station of a wireless communication network in accordance with an embodiment of the present invention. Referring to the network topology shown in FIG. 2 The composition is described in detail to describe the flow of signal forwarding in the relay station R1.

First, in step S11, the relay station R1 determines whether a plurality of network devices occupy part or all of the same time-frequency resources when communicating with the relay station.

If the plurality of network devices occupy part or all of the same time-frequency resource when communicating with the relay station, then in step S12, the relay station R1 is identical to the part of the plurality of network devices and the local relay station based on a predetermined rule. The communication signal on the time-frequency resource is processed. On those different time-frequency resources, the relay station R1 directly processes the communication signals on the respective time-frequency resources. This is similar to the processing of the existing relay station serving only one network device, and the present invention will not be described again.

The signal forwarding procedure for the same time-frequency resource shown in Figure 6 contains two scenarios: The first scenario: The relay station R1 receives signals from different source network devices on some of the same time-frequency resources; Relay station R1 sends different signals to multiple target network devices on some of the same time-frequency resources. The processing situation of the relay station in these two cases will be described in detail below with reference to Fig. 2 .

1. The first situation:

Referring to the network topology shown in FIG. 2, in the downlink, the first scenario specifically includes: the relay station R1 is received by the base station B2 and the base station B2 on the same time-frequency resource, and is respectively sent to the mobile station M3 and The signal of the mobile station M3, in the uplink, the first case specifically includes: the relay station R1 is received on some of the same time-frequency resources and transmitted by the mobile station M3 and the mobile station M3' to the base station B2 and the base station B2', respectively. signal of.

The following downlink is used as an example to describe the processing flow in the relay station R1 in detail.

First, the relay station R1 judges whether or not to receive signals from the base station B2 and the base station B2 and to the mobile station M3 and the mobile station M3' on some of the same time-frequency resources. Specifically, a manner of determining is determined according to time-frequency resource mapping signaling sent by the base station B2 and the base station B2'.

If the relay station R1 receives signals from the base station B2 and the base station B2 on some of the same time-frequency resources (ie, the base station B2 and the base station B2, and sends signals on some of the same time-frequency resources, the mixed signal is referred to as a space division multiplexed signal. ), based on the first predetermined rule and The base station B2 and the base station B2, and the channel related information to the relay station R1 perform MIMO detection and decoding on the received space division multiplexed signal to separate the signals from the base station B2 and the base station B2.

Specifically, the predetermined rule refers to a MIMO detection decoding method, which is mainly divided into two types of linear and nonlinear methods. Common linear detection and decoding methods include a zero-forcing method, a minimum mean square error method, and the like, and various thereof. Deformation and simplification; Common non-linear detection and decoding methods include the use of interference cancellation techniques based on the zero-forcing and minimum mean square error methods, as well as the maximum likelihood method and various simplified deformations.

Specifically, the channel related information includes a channel transmission matrix composed of channel transmission coefficients or various forms of channel transmission coefficients, for example, in the formula (2), preferably, the channel transmission coefficient is an instantaneous estimation value.

The relay station R1 acquires a plurality of ways of obtaining channel-related information from the base station Β2 and the base station Β2 to the relay station R1. Usually, the relay station R1 estimates the base station Β2 and the base station Β2 based on the predetermined pilot signal, and the channel transmission coefficient to the relay station R1 as the channel-related information required for decoding. Specifically, how the channel transmission coefficient is estimated should be common knowledge that one of ordinary skill in the art should know, and the present invention will not be described in detail.

After acquiring the channel transmission coefficients of the base station Β2 and the base station Β2 to the relay station R1, the relay station R1 may perform MIMO detection and decoding on the received spatial multiplexed mixed signal based on the zero forcing method shown in the formula (2) to separate out Signals from base station B2 and base station B2.

2. The second case:

Referring to the network topology shown in Fig. 2, in the downlink, the second scenario specifically includes: The relay station R1 transmits signals to the mobile station M3 and the mobile station M3 on some of the same time-frequency resources. In the uplink, the second scenario specifically includes: The relay station R1 transmits signals to the base station B2 and the base station B2 on some of the same time-frequency resources.

The following process is still taken as an example to describe the processing flow in the relay station R1 in detail.

First, the relay station R1 determines whether it will receive on some of the same time-frequency resources. The signals transmitted by the base station B2 and the base station B2' to the mobile station M3 and the mobile station M3 are transmitted to the mobile station M3 and the mobile station M3. Specifically, a manner of determining is determined according to time-frequency resource mapping signaling sent by the base station B2 and the base station B2.

If the relay station R1 needs to transmit signals to the mobile station M3 and the mobile station M3 on some of the same time-frequency resources, then the signals to be transmitted on the same time-frequency resources need to be pre-coded based on the second predetermined rule, so that Each mobile station receives as much as possible only the signals transmitted to it, and less frequently receives signals transmitted to other mobile stations on the same time-frequency resource.

Specifically, the second predetermined rule refers to a multi-user SDMA pre-coding process, which is mainly divided into two types of linear and nonlinear methods. Common linear pre-coding methods include inverse channel zero-forcing, minimum mean square error, and block diagonalization. Zero-forcing method, beamforming method or based on predetermined code calligraphy, etc., and their various deformations, simplifications, such as multi-user feature pattern transmission methods, etc.; common nonlinear precoding methods include the paper-grain coding method and its deformation.

Specifically, the coefficients of the precoding process or the precoding matrix can be determined based on the channel related information as shown in the formula (4). The channel related information includes but is not limited to: a channel transmission matrix composed of channel transmission coefficients obtained by instantaneous or long-term statistics of the relay station R1 to the mobile station M3 and the mobile station M3; or according to the relay station R1 to the mobile station M3 and the mobile station M3' The number of the predetermined codebook determined by the instantaneous or long-term channel transmission coefficient. Of course, in this case, the information of the predetermined codebook is pre-stored in the relay station R1. In addition, those skilled in the art should know that the channel related information also includes other various forms of channel correlation information adopted by various precoding processes such as a covariance matrix of channel transmission coefficients and feature vectors, and the present invention is no longer - enumerated .

There are various ways in which the relay station R1 acquires channel-related information of its channel to the mobile station M3 and the mobile station M3. One possible implementation is as follows: The mobile station M3 and the mobile station M3 estimate the channel transmission coefficients of the relay stations R1 to their channel according to predetermined pilot signals, and feed back the quantized channel transmission coefficients to the relay station R1; or the mobile station M3 And the mobile station M3, which feeds back the number of the predetermined codebook according to the respective channel transmission coefficients to the relay station R1; for the uplink and downlink symmetric channel (such as a time division duplex system), the relay station R1 itself can also estimate the uplink signal by the uplink signal. To mobile station M3 and mobile station The channel transmission coefficient of M3, and then the precoding coefficient is determined according to, for example, equation (4). Specifically, how the channel transmission coefficients are estimated and how the mobile station M3 and the mobile station M3 feed back the channel transmission coefficients or the number of the predetermined codebook determined according to the channel transmission coefficients of the relay station R1 to the mobile station M3 and the mobile station M3' (see reference) Document 8) should be common knowledge that one of ordinary skill in the art should know, and the present invention will not be described in detail.

For the scenario of the network topology with multiple relay stations as shown in Figures 3 and 5, each relay station determines whether it needs to be co-located with other one or more relay stations according to the indication of base station B2 or base station B2'. Different signals are sent to different target network devices on the same time-frequency resource. A plurality of relay stations can perform the same function as the relay station R1 shown in Fig. 2, so that the target network device obtains a higher radio frequency and diversity gain, that is, a plurality of relay stations perform macro diversity functions. Of course, multiple relay stations can also perform distributed spatial multiplexing or space-time coding on the basis of the aforementioned precoding to obtain better multiplexing or diversity gain.

Figure 7 is a block diagram showing the structure of a forwarding device 10 for signal forwarding in a co-administration relay station of a wireless communication network in accordance with an embodiment of the present invention. The forwarding device 10 includes a judging device 11, a processing device 12, a first obtaining device 13, and a second obtaining device 14. It should be noted that, for the sake of brevity, the sub-devices in many preferred embodiments are shown together in FIG. 7, and those skilled in the art should understand according to the teachings of the present specification, wherein only the judging device 11 and the processing device 12 are implemented. The device necessary for the present invention, the other sub-devices are optional devices. The process of signal forwarding by the forwarding device 10 in the relay station R1 will be described in detail below with reference to the network topology diagram shown in FIG.

First, the judging means 11 judges whether or not a plurality of network devices occupy the same time-frequency resources as those of the own relay station.

If the plurality of network devices share some or all of the same time-frequency resources when communicating with the relay station, the processing device 12 compares the plurality of source or target network devices to the same or all of the time-frequency resources of the local relay station based on the predetermined rule. The communication signal on is processed.

The above process of signal forwarding for the same time-frequency resource includes two scenarios: The first scenario: the relay station R1 receives signals from different source network devices on some of the same time-frequency resources; the second scenario: the relay station R1 is Some identical time-frequency resources Send different signals to multiple target network devices. The processing of the forwarding device 10 in the relay station R1 in these two cases will be described in detail below with reference to FIG. 2, respectively.

1. The first situation:

Referring to the network topology shown in FIG. 2, in the downlink, the first scenario specifically includes: the relay station R1 is received by the base station B2 and the base station B2 on the same time-frequency resource, and is respectively sent to the mobile station M3 and The signal of the mobile station M3, in the uplink, the first scenario specifically includes: the relay station R1 is received by the mobile station M3 and the mobile station M3' to the base station B2 and the base station B2, respectively, on some of the same time-frequency resources, signal of.

The following downlink is taken as an example to describe the processing procedure of the forwarding device 10 in detail.

First, the judging device 11 determines, according to the time-frequency resource mapping signaling from the base station B2 and the base station B2, whether to receive from the base station B2 and the base station B2' to the mobile station M3 and the mobile station M3 respectively on some of the same time-frequency resources. signal of.

If the relay station R1 receives signals from the base station B2 and the base station B2 on some of the same time-frequency resources (ie, the base station B2 and the base station B2, and sends signals on some of the same time-frequency resources, the mixed signal is referred to as a space division multiplexed signal. The processing device 12 performs MIMO detection decoding on the received space division multiplexed signal based on the first predetermined rule and the base station B2 and the base station B2, and the channel related information to the relay station R1, to receive the from the base station B2 and the base station B2'. The signal is separated.

Specifically, the first predetermined rule refers to a MIMO detection and decoding method, and is mainly divided into two types of linear and nonlinear methods. Common linear detection and decoding methods include a zero-forcing method, a minimum mean square error method, and the like, and various thereof. Deformation and simplification; Common non-linear detection and decoding methods include the use of interference cancellation techniques based on the zero-forcing and minimum mean square error methods, as well as the maximum likelihood method and various simplified deformations.

Specifically, the channel related information includes a channel transmission matrix composed of channel transmission coefficients or various other forms of channel transmission coefficients, for example, preferably, in Equation (2), the channel transmission coefficient is an instantaneous estimation value.

Preferably, the transmission device 10 further includes a first acquisition device 13, a first acquisition device 13 There are various ways to obtain the channel-related information from the base station B2 and the base station B2 to the relay station R1. Generally, the first obtaining means 12 estimates the channel transmission coefficients of the base station B2 and the base station B2 to the relay station R1 as the channel related information required for decoding, based on the predetermined pilot signal. Specifically, how the channel transmission coefficient is estimated should be common knowledge that one of ordinary skill in the art should know, and the present invention will not be described in detail.

After acquiring the channel transmission coefficients of the base station B2 and the base station B2 to the relay station R1, the relay station R1 may detect and decode the received spatial multiplexing mixed signal based on the zero forcing method shown in the formula (2) to separate the Signals from base station B2 and base station B2.

2. The second case:

First, the determining device 11 determines, according to the time-frequency resource mapping signaling from the base station B2 and the base station B2, whether the relay station R1 is to transmit the received base station B2 and the base station B2' to the mobile station M3 on some of the same time-frequency resources. The signal of the mobile station M3 is transmitted to the mobile station M3 and the mobile station M3.

If the relay station R1 needs to transmit signals to the mobile station M3 and the mobile station M3 on some of the same time-frequency resources, the processing device 12 needs to pre-code the signals to be transmitted based on the second predetermined rule on the same time-frequency resources to Each mobile station is allowed to receive only the signals transmitted to it as much as possible, and less frequently receive signals transmitted to other mobile stations on the same time-frequency resource.

Specifically, the second predetermined rule refers to a multi-user SDMA pre-coding process, which is mainly divided into two types of linear and nonlinear methods. Common linear pre-coding methods include inverse channel zero-forcing, minimum mean square error, and block diagonalization. Zero-forcing method, beamforming method or based on predetermined code calligraphy, etc., and their various deformations, simplifications, such as multi-user feature pattern transmission methods, etc.; common nonlinear precoding methods include the paper-grain coding method and its deformation. . Specifically, the coefficients of the precoding process or the precoding matrix may be determined according to channel related information, as shown in formula (4). Specifically, the channel related information includes, but is not limited to: a channel transmission matrix, a covariance matrix, a feature vector, etc. formed by channel transmission coefficients obtained by instantaneous or long-term statistics of the relay station R1 to the mobile station M3 and the mobile station] VI3; The number of the predetermined codebook determined by the instantaneous or long-term channel transmission matrix, the covariance matrix, and the feature vector of the relay station R1 to the mobile station M3 and the mobile station M3 (refer to Reference 8), of course, in this case, the relay station R1 The information of the predetermined code book is pre-stored.

Preferably, the transmission device 10 further includes second acquisition means 14, and the second acquisition means 14 obtains a plurality of ways of channel-related information of a plurality of channels of the relay station R1 to the mobile station M3 and the mobile station M3. A possible acquisition manner is as follows: the mobile station M3 and the mobile station M3, estimating the channel transmission coefficients of the relay stations R1 to their channels according to predetermined pilot signals, and feeding back the quantized channel transmission coefficients to the second obtaining device 14, or The mobile station M3 and the mobile station M3 select the number of the predetermined codebook according to the respective channel transmission coefficients and feed back the number to the second acquiring device 14; for the uplink and downlink symmetric channel (such as a time division duplex system), The second acquisition means 14 estimates the channel transmission coefficients of its relay station R1 to the mobile station M3 and the mobile station M3 from the uplink signal, and then determines the precoding coefficient according to, for example, equation (4). Specifically, how the channel transmission coefficients are estimated and how the mobile station M3 and the mobile station M3 feed back the channel transmission coefficients or determine the number of the predetermined codebook according to the channel transmission coefficients of the relay station R1 to the mobile station M3 and the mobile station M3 should be ordinary in the art. Common knowledge that the skilled person should know, the present invention will not be described again.

For the scenario of the network topology with multiple relay stations as shown in FIG. 3 and FIG. 5, the judging device 11 judges whether it needs to be the same as the other one or more relay stations according to the indication of the base station B2 or the base station B2. Different signals are sent to different target network devices on time-frequency resources.

A plurality of relay stations can perform exactly the same functions as the relay station R1 shown in Fig. 2, so that the target network device obtains a higher radio frequency and diversity gain, i.e., multiple relay stations perform macro diversity functions. Of course, multiple relay stations can also perform distributed spatial multiplexing or space-time coding on the basis of the aforementioned precoding to obtain better multiplexing or diversity gain.

The specific embodiments of the present invention have been described above. It should be understood that the present invention It is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the appended claims.

Claims

Claim

A method for signal forwarding in a relay station of a wireless communication network, wherein the relay station includes a plurality of receiving and transmitting antennas, wherein the method comprises the following steps:

a. judging whether a plurality of network devices occupy part or all of the same time-frequency resources when communicating with the relay station;

b. if the plurality of network devices occupies part or all of the same time-frequency resource when communicating with the relay station, based on a predetermined rule and according to channel related information of multiple channels between the plurality of network devices and the relay station The communication signals between the plurality of network devices and the relay station on the part or all of the same time-frequency resources are processed.

2. The method according to claim 1, wherein the step a further comprises the following steps:

- determining whether the relay station receives signals from the plurality of network devices on the part or all of the same time-frequency resources;

The predetermined rule includes a first predetermined rule, and the step b further includes the following steps: the signals of the plurality of network devices, based on the first predetermined rule and according to the channel correlation of the plurality of network devices to the plurality of channels of the relay station The information is processed by the mixed signal received by the relay station and transmitted by the plurality of network devices to obtain signals from the respective network devices.

3. The method according to claim 2, further comprising the following steps before the step b:

- obtaining channel related information of the plurality of network devices to the plurality of channels of the relay station

4. The method according to claim 1, wherein the step a further comprises the following steps:

- determining whether the relay station needs to send different signals to the plurality of network devices on the part or all of the same time-frequency resources; The predetermined rule includes a second predetermined rule, and the step b further includes the following steps: - if the relay station needs to send different signals to the plurality of network devices on the part or all of the same time-frequency resources, based on the And pre-coding the different signals that the relay station needs to send to the plurality of network devices according to the channel-related information of the plurality of channels of the relay station to the plurality of network devices.

The method according to claim 4, wherein the step a further comprises the following steps:

- Determining whether the relay station and one or more other relay stations need to be in the section or the step b further comprises the following steps:

- if the present relay station and the one or more other relay stations need to jointly transmit different signals to the plurality of network devices on the part or all of the same time-frequency resources, based on the second predetermined rule and according to the present relay station to the plurality of The channel-related information of the plurality of channels of the network device pre-codes different signals that the relay station needs to send to the plurality of network devices to jointly transmit different signals to the plurality of networks together with one or more other relay stations device.

The method according to claim 4 or 5, further comprising the following steps before the step b:

Obtaining channel-related information of multiple channels of the relay station to the plurality of network devices

'&.

The method according to claim 2 or 3, wherein the first predetermined rule comprises a MIMO detection decoding method.

8. The method of claim 7, the MIMO detection decoding rule comprising any one of the following:

- forced zero method;

- minimum mean square error method;

- Maximum likelihood method.

The method according to any one of claims 4 to 6, wherein the second predetermined rule comprises a multi-user SDMA precoding method.

10. The method of claim 9, the multi-user SDMA pre-coding rules comprising any of the following:

- beamforming method;

- inverse channel forcing zero method;

- minimum mean square error method;

- block diagonalization forced zero method;

- Stained paper coding method;

- Based on the predetermined code calligraphy.

The method according to any one of claims 1 to 10, the network device comprising any one of the following:

- multiple base stations;

- multiple mobile stations;

- multiple relay stations;

- one or more relay stations and one or more base stations;

- One or more relay stations with one or more mobile stations.

12. A forwarding device for signal forwarding in a relay station of a wireless communication network, wherein the relay station comprises a plurality of receiving and transmitting antennas, wherein the forwarding device comprises:

a determining device, configured to determine whether a plurality of network devices occupy part or all of the same time-frequency resources when communicating with the relay station;

a processing device, configured to: if the plurality of network devices share part or all of the same time-frequency resources when communicating with the relay station, based on a predetermined rule and according to channel related information of the plurality of network devices and the plurality of channels of the relay station The communication signals between the plurality of network devices and the relay station on the part or all of the same time-frequency resources are processed.

The forwarding device according to claim 12, wherein the determining device is further configured to:

The predetermined rule includes a first predetermined rule, and the processing device is further configured to: - if the present relay station receives signals from the plurality of network devices on all or part of the same time-frequency resource, based on a first predetermined rule and based on channel correlation of the plurality of network devices to a plurality of channels of the relay station The information is processed by the mixed signal received by the relay station and transmitted by the plurality of network devices to obtain signals from the respective network devices.

The forwarding device according to claim 13, further comprising: first acquiring means, configured to acquire channel related information of a plurality of channels of the plurality of network devices to the relay station.

- determining whether the relay station needs to send different signals to the plurality of network devices on the part or all of the same time-frequency resources;

The predetermined rule includes a second predetermined rule, and the processing device is further configured to:

- if the present relay station needs to transmit different signals to the plurality of network devices on the part or all of the same time-frequency resources, based on the second predetermined rule and according to the plurality of channels of the relay station to the plurality of network devices The channel related information performs precoding processing on different signals that the relay station needs to send to the plurality of network devices.

The forwarding device according to claim 15, wherein the determining device is further configured to:

Determining whether the relay station and the one or more other relay stations need to jointly transmit different signals to the plurality of network devices on the part or all of the same time-frequency resources; the processing device is further configured to:

- if the present relay station and one or more other relay stations need to transmit the partial relay rules in the part or all of the two predetermined rules and according to the channel-related information of the plurality of channels of the relay station to the plurality of network devices to the plurality of networks Different signals of the device are precoded to jointly transmit different signals to the plurality of network devices in conjunction with one or more other relay stations.

17. The forwarding device according to claim 15 or 16, wherein Includes:

The second obtaining means is configured to acquire channel related information of the plurality of channels of the relay station to the plurality of network devices.

The forwarding device according to claim 13 or 14, wherein the first predetermined rule comprises a MIMO detection decoding method.

19. The forwarding device of claim 18, wherein the MIMO detection decoding rule comprises any one of the following:

- forced zero method;

- minimum mean square error method;

- Maximum likelihood method.

The forwarding device according to any one of claims 15 to 17, wherein the second predetermined rule comprises a multi-user SDMA precoding method.

21. The forwarding device of claim 20, the multi-user SDMA pre-coding rules comprising any one of the following:

- beamforming method;

- inverse channel forcing zero method;

- minimum mean square error method;

- block diagonalization forced zero method;

- Stained paper coding method;

- Based on the predetermined code calligraphy.

The forwarding device according to any one of claims 12 to 21, wherein the plurality of network devices comprise any one of the following:

- multiple base stations;

- multiple mobile stations;

- multiple relay stations;

- one or more relay stations and one or more base stations;

- One or more relay stations with one or more mobile stations.