CN101505482A - Semi-distribution type resource distribution method and system - Google Patents

Abstract

The invention relates to a semi-distributed resource allocation method, comprising the following steps: the base station obtains the channel state information of the direct transmission link fed back by the direct transmission user, the channel state information of the first hop link fed back by the relay station, and the estimated second The average rate information of the hop link; the base station allocates resources to the relay station and direct transmission users according to the above information; the relay station redistributes the resources allocated to the relay station to the relay according to the channel state information of the second hop link fed back by the relay user user. The invention also relates to a semi-distributed resource allocation system. According to the characteristics of the relay system in terms of network topology, etc., the present invention decomposes the resource allocation method into two functional entities for distributed implementation, reduces the feedback overhead and algorithm complexity of the relay user's second-hop channel state information, and effectively It improves the user satisfaction rate of the network, ensures the communication service quality of users in the mobile environment, and enhances the system throughput and resource utilization.

Description

Semi-distributed resource allocation method and system

technical field

The invention relates to the field of mobile communication, in particular to a semi-distributed resource allocation method and system.

Background technique

Future mobile communication systems need to support high-speed transmission under high mobility and have wider service coverage. This requires not only the adoption of advanced transmission technologies, but also the support of new network architectures. Cellular relay mobile communication system (referred to as cellular relay system) is a research hotspot in recent years. It can obtain space diversity gain, expand network coverage, increase system capacity, and enhance system performance through cooperative transmission of relay nodes and optimal allocation of resources. Organizations such as IEEE802.11, IEEE802.16 and European WINNER have clearly proposed the concept of "relay" and multi-hop cooperative transmission, and are working on standardization. Therefore, the relay system has become a very attractive and competitive future wireless communication network technology architecture solution.

In a cellular relay system, a user terminal can access the network through a base station, or through a relay station in a two-hop transmission mode. It can be considered that there are two types of users in the system. It is precisely because the diversity of users and the time-varying nature of the wireless propagation channel will affect the transmission quality of the user's current link in real time. In order to ensure a high throughput of the network and high user satisfaction, the system needs to Changes are adjusted and new communication links are allocated on the fly. As an important radio resource management function, resource allocation is also a key module function of the mobile communication system. Its process design and allocation mechanism will directly affect the performance of the entire network.

The application of relay technology has brought new challenges to the resource allocation mechanism of the cellular system, and the original resource allocation scheme will not be able to adapt to the new system requirements.

First, in a traditional cellular mobile communication network, resource allocation only needs to be considered between two network elements, the base station and the terminal. With the introduction of relay technology, in addition to the original base stations and terminals, new network elements such as relay stations have been added to the network. The complexity of network topology and the diversification of user types will make the cellular relay network Resource allocation strategies are necessarily more complex.

Secondly, in the case of multiple users, the resources allocated by the wireless communication system need to consider at least two-dimensional joint optimization of time and frequency. The introduction of relay stations, while changing the network topology, also brings spatial changes, that is, three-dimensional optimization in space, time domain, and frequency domain needs to be considered when resource allocation, which also increases the difficulty of the resource management module accordingly.

Thirdly, the existing cellular relay system basically adopts a centralized or distributed resource allocation method. For the centralized method, it can effectively maximize the throughput of the system and guarantee the QoS of the users. After the introduction of the relay station, how to use its resource management function has become a major difficulty. In addition to the inherent advantages of expanding coverage and improving the signal-to-noise ratio of each hop link, if the traditional centralized resource allocation mechanism is used, not only the management function of the relay station cannot be reflected and utilized, but also because the multi-hop channel information feedback will give the system With the addition of huge overhead, the data processing and resource allocation decisions at the base station will become more complicated. As for the distributed method, it can effectively reduce the information feedback amount of the relay terminal in the cellular relay system, and make full use of the resource management function of the relay station; Due to the unknown nature of the two-hop link, its resource allocation cannot optimize the throughput and user satisfaction most effectively. If a distributed resource allocation scheme is sought from the perspective of non-cooperative game or cooperative game, not only must sacrifice a certain algorithm complexity, but also It is difficult to achieve the optimal performance of the system.

Regardless of the resource allocation method, it is necessary to ensure the user's communication quality as much as possible when the user's channel state changes, so as to improve user satisfaction and system throughput. Obviously, various traditional centralized resource allocation schemes, such as round-robin resource allocation schemes, maximum carrier-to-interference ratio resource allocation schemes, proportional fairness schemes, etc., are no longer suitable for cellular relay systems, so they should be targeted at cellular relay systems. characteristics, and reconsider the resource allocation problem in the case of introducing relay technology.

Contents of the invention

The purpose of the present invention is to propose a semi-distributed resource allocation method and system suitable for cellular relay systems, which can make full use of the resource management function of the relay station, a new network element, reduce the feedback overhead of the system, and improve the effective utilization of resources , increase user satisfaction, and enhance system throughput.

To achieve the above object, the present invention provides a semi-distributed resource allocation method, comprising the following steps:

The base station obtains the channel state information of the direct transmission link fed back by the direct transmission user, the channel state information of the first-hop link fed back by the relay station, and the average rate information of the second-hop link estimated by the relay station;

The base station allocates resources to relay stations and direct transmission users according to the channel state information of the direct transmission link, the channel state information of the first-hop link, and the average rate information;

The relay station reallocates resources allocated to the relay station to the relay user according to the channel state information of the second hop link fed back by the relay user.

Further, before the relay station feeds back the average rate information of the second hop link, the following steps are also included:

The relay station receives the channel state information of the second-hop link fed back by the relay user, and estimates the average rate information of the second-hop link according to the channel state information of the second-hop link.

Further, the operation of estimating the average rate information of the second hop link is specifically:

The relay station performs weighting processing on the channel information of the relay user on each subcarrier of the second hop link, and estimates the average rate information of the second hop link.

Further, the operation of the base station allocating resources to relay stations and direct transmission users according to the channel state information of the direct transmission link, the channel state information of the first hop link, and the average rate information specifically includes:

Treating all relay stations as an overall relay station, the base station allocates system resources to the direct transmission users and the overall relay station;

According to the average rate information of the second hop link, the base station estimates the number of subcarriers required by each relay station to support the transmission of the second hop link, and assigns the resources allocated to the overall relay station according to the The estimated number of subcarriers is allocated to each relay station in proportion.

Further, the operation of allocating system resources to the direct transmission user and the overall relay station is specifically:

The base station allocates resources to the direct transmission users and the overall relay station on the premise of meeting the minimum transmission rate requirements of different service types and maximizing system throughput as a criterion.

Further, the operation of reallocating the resource allocated to the relay station to the relay user is specifically:

The relay station adjusts the subcarrier allocation and the power on each subcarrier to allocate the second hop link according to the transmission rate of the relay user on the first hop link and according to the channel state information of the second hop link fed back by the relay user Route resources to achieve two-hop rate balance.

To achieve the above object, the present invention provides a semi-distributed resource allocation system, comprising:

The first channel state acquisition module is set in the base station and is used to obtain the channel state information of the direct transmission link fed back by the direct transmission user, the channel state information of the first hop link fed back by the relay station, and the second hop link estimated by the relay station The average speed information of the road;

The first resource allocation module is set in the base station and is used to allocate resources to the relay station and the direct transmission user according to the channel state information of the direct transmission link, the channel state information and the average rate information of the first hop link;

The second channel state acquisition module is set in the relay station and is used to obtain the channel state information of the second hop link fed back by the relay user;

The second resource allocation module is set in the relay station, and is used to re-allocate the resource allocated to the relay station to the relay user according to the channel state information of the second hop link.

Further, it also includes an average rate estimation module, which is set in the relay station, and is used for estimating the average rate information of the second-hop link according to the channel state information of the second-hop link.

Further, the first resource allocation module specifically includes:

A relay station overall allocation unit, configured to regard all relay stations as an overall relay station, and the base station allocates system resources to the direct transmission users and the overall relay station;

A subcarrier estimation unit, configured to estimate the number of subcarriers required by each relay station to support the transmission of the second hop link;

The relay station individual allocation unit is configured to allocate the resources allocated to the overall relay station to each relay station in proportion to the estimated number of subcarriers.

Further, the second resource allocation module specifically includes:

The subcarrier adjustment unit is used to adjust subcarrier allocation and power allocation on each subcarrier according to the transmission rate of the relay user on the first hop link and the channel state information of the second hop link fed back by the relay user Resources of the second hop link to achieve two-hop rate balance.

Based on the above technical solution, under the premise of fully utilizing the resource management function of the relay station, the present invention decomposes the resource allocation method into two functional entities for distribution and implementation according to the characteristics of the relay system in terms of network topology, etc. The relay station achieves two-hop rate equalization, which not only reduces the feedback overhead and algorithm complexity of the relay user's second-hop channel state information, but also makes full use of the relay station as a network element, effectively improving the user satisfaction rate of the network and ensuring the user's The quality of communication service in the mobile environment enhances system throughput and resource utilization, and has strong practicability.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

FIG. 1 is a schematic structural diagram of a cellular relay network involved in the present invention.

2a-2c are schematic diagrams of centralized resource allocation in the prior art, semi-distributed resource allocation in the present invention, and distributed resource allocation in the prior art, respectively.

FIG. 3 is a schematic flowchart of an embodiment of a method for allocating semi-distributed resources in the present invention.

Fig. 4 is a schematic flowchart of another embodiment of the semi-distributed resource allocation method of the present invention.

FIG. 5 is a schematic diagram of resource allocation in the cellular relay network involved in the present invention.

FIG. 6 is a schematic diagram of relay user two-hop equalization involved in the present invention.

FIG. 7 is a schematic structural diagram of an embodiment of the semi-distributed resource allocation system of the present invention.

FIG. 8 is a schematic structural diagram of another embodiment of the semi-distributed resource allocation system of the present invention.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

As shown in FIG. 1 , it is a schematic structural diagram of a cellular relay network involved in the present invention. The cellular relay network is composed of multiple cells, each cell contains a base station BS (BaseStation), one or more relay stations RS (Relay Station) and one or more mobile user terminals MS (Mobile Station). The direct transmission user d-MS can connect to the BS through the direct transmission link G ₀ to access the network, and the relay user r-MS can establish the second hop link G ₂ and the first hop link G ₁ with the base station through the relay station RS BS connection to access the network. An example of a TDD-based frame structure is also given in FIG. 1 .

The so-called direct transfer user d-MS refers to a mobile terminal whose access station is a base station BS, and the relay user r-MS refers to a mobile terminal whose access station is a relay station RS. The so-called access station refers to the equipment directly connected to the mobile terminal when accessing the network, and its access method can be based on the maximum received power, the minimum path loss, the maximum channel capacity, or other criteria. The so-called first-hop link refers to the communication connection between the base station BS and the relay station RS, and the second-hop link refers to the communication connection between the relay station RS and the relay user r-MS, also called a relay link.

The present invention is applicable to the above-mentioned cellular relay system, and the resource allocation method adopted by it is different from the centralized resource allocation and distributed resource allocation in the prior art, that is, semi-distributed resource allocation. The so-called semi-distributed resource allocation method means that resource allocation for relay users in the network is performed in the base station BS and the relay station RS respectively, but the allocation of the two is not completely independent. Among them, the resource allocation made by the base station BS will depend on the weighted information about the link from the relay station RS to the relay user r-MS fed back by the relay station RS, and the allocation of the relay station RS can also consider the link from the base station BS to the relay station RS as needed , and the rate equalization of the link from the relay station RS to the relay user r-MS.

The following compares the three resource allocation methods of the prior art and the present invention applied to the cellular relay system. As shown in Figures 2a-2c, they are schematic diagrams of centralized resource allocation in the prior art, semi-distributed resource allocation in the present invention, and distributed resource allocation in the prior art, respectively. The main differences between the three methods are explained below:

1) From the perspective of information feedback, the centralized resource allocation method requires the relay station to feed back all the channel information of the second hop of the relay user; the semi-distributed resource allocation method proposed in the present invention only requires the relay station to feed back the second hop of the relay user. The average rate of the hop is fed back; while the distributed resource allocation method does not need the channel information feedback of the second hop.

2) From the perspective of the function of the network access station, the centralized resource allocation function is concentrated on the base station, and the relay station does not participate in resource allocation, but only forwards the transmission signal; the semi-distributed resource allocation proposed by the present invention will be performed separately at the base station and the relay station , and the base station can pre-allocate resources for relay users, and the relay station can perform two-hop equalization processing for relay users; distributed resource allocation is also performed separately at the base station and relay station, but the resource allocation of the two functional entities is completely independent of.

3) From the perspective of resource allocation, using a centralized method, the base station can perform transmission rate estimation based on the complete channel state information of two hops during resource scheduling; using the semi-distributed method proposed by the present invention, the base station can be based on the relay station With the distributed method, the base station cannot obtain the channel state information of the second hop, so it cannot predict the transmission rate of the relay user, and can only process it randomly or according to other criteria.

As shown in FIG. 3 , it is a schematic flowchart of an embodiment of the semi-distributed resource allocation method of the present invention. This embodiment includes the following steps:

Step 101, the base station obtains the channel state information of the direct transmission link fed back by the direct transmission user, the channel state information of the first-hop link fed back by the relay station, and the average rate information of the second-hop link estimated by the relay station;

Step 102, the base station allocates resources to relay stations and direct transmission users according to the channel state information of the direct transmission link, the channel state information of the first-hop link, and the average rate information;

In step 103, the relay station reallocates resources allocated to the relay station to the relay user according to the channel state information of the second hop link fed back by the relay user.

In the above technical solution, the resources may be time slots, frequency band resources and/or power resources allocated by the system to the mobile terminal, and the channel state information refers to the channel state of the link on each subcarrier.

The scheme of the embodiment of the present invention makes full use of the network element of the relay station, decomposes the resource allocation method into two functional entities, the base station and the relay station, and implements it in a semi-distributed form, reducing the feedback of the second-hop channel state information of the relay user The overhead and algorithm complexity effectively improve the user satisfaction rate of the network, ensure the communication service quality of users in the mobile environment, enhance the system throughput and resource utilization, and have strong practicability.

中继站的下行最大发射功率为

第k用户在第m小区第i跳第n号载波上的信道状态为

m＝1，...，M，n＝1，...，N，i＝0，1，2，其中i＝0表示直传链路。系统采用时分半双工的方式，对于中继用户来讲，时隙资源分成ξ，1-ξ两部分，以支持中继用户的两跳传输，0<ξ<1。As shown in FIG. 4 , it is a schematic flowchart of another embodiment of the semi-distributed resource allocation method of the present invention. In this embodiment, it is assumed that the system has M co-channel cells, the frequency reuse factor is 1, and the system bandwidth is B, which are divided into N orthogonal sub-channels. There are K users evenly distributed in the system, among which there are K _d direct transmission users and K _r relay users, and the maximum downlink transmission power of the base station is

The maximum downlink transmit power of the relay station is

The channel state of the k-th user on the n-th carrier of the i-th hop in the m-th cell is

m=1, . . . , M, n=1, . . . , N, i=0, 1, 2, where i=0 indicates a direct transmission link. The system adopts time-division half-duplex mode. For relay users, time slot resources are divided into ξ and 1-ξ to support two-hop transmission of relay users, 0<ξ<1.

The first step is to determine the channel conditions of various links according to the structure of the cellular relay system, including the channel conditions of the direct transmission link, the first hop link and the second hop link, and may also include the measured channel information, namely Various factors that affect the signal exist in the wireless propagation process such as the propagation loss of the signal in free space, shadow fading, and multipath fading.

The direct transmission user feeds back the measured channel state information of the user link to the access station (step 1a), and at the same time, the relay station feeds back the channel state information of the first-hop link to the base station (step 1b).

根据香农公式估计每个中继用户在第二跳所有载波上所能传输的平均速率

以线性等权重加权为例，对于第k_r个中继用户，其平均速率

为In the second step, the relay station based on the channel information fed back by the relay user

Estimate the average rate that each relay user can transmit on all carriers in the second hop according to Shannon's formula

Taking linear equal-weight weighting as an example, for the k _rth relay user, its average rate

for

${\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; c</span>}}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\frac{\mathrm{<span\; class="notranslate">\; B</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

是第k_r中继用户在第m小区第i跳第n号载波上的信噪干扰比in,

is the signal-to-noise-interference ratio of the k- _th relay user on the i-th hop n-th carrier in the m-th cell

${\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; G</span>}}_{\mathrm{<span\; class="notranslate">\; kr</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; p</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1,2</span>}<span\; class="notranslate">\; .</span>$

Among them, p ^m (i, n) is the transmission power of the access station to the k-th user on the i-th hop n-th carrier in the m-th cell, σ ² is the noise power, and ^Im (i, n) is the k-th user The co-channel interference of the entire network on the nth carrier of the i-th hop in the m-th cell

${\mathrm{<span\; class="notranslate">\; I</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&prime;</span><span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; G</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; p</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>$

是信噪比门限，有 ${\mathrm{\&Gamma;}}_{k_d}^m=1.5/-\ln \left({5\mathrm{BER}}_{k_d}^m\right),$

是第k用户的误比特率要求。In formula (1),

is the signal-to-noise ratio threshold, and ${\mathrm{\&Gamma;}}_{k_d}^m=1.5/-\ln \left({5\mathrm{BER}}_{k_d}^m\right),$

is the bit error rate requirement of the kth user.

反馈至基站(步骤2)。Average rate per relay user that the relay will estimate

Feedback to the base station (step 2).

In the third step, the base station makes the first resource allocation based on the channel state information fed back by the direct transmission user and the relay station based on the minimum transmission rate requirement of each user. The allocated resources include resources such as time slots, frequency bands, and power, such as Figure 5 shows.

Let the minimum transmission rate requirement vector of all users in the system be $R^m=[R_1^m,R_2^m,...,R_K^m],$ The transmission rate vector of each user estimated by the base station on each subcarrier is $c_{\mathrm{no}}^m=[c_{\mathrm{no},1}^m,c_{\mathrm{no},2}^m,...,c_{\mathrm{no},K}^m],$

${\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}\\ \frac{\mathrm{<span\; class="notranslate">\; B</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&xi;</span>}{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Let the allocation identification factor of the system subcarrier be a _{n, k} , which means that the nth subcarrier is allocated to the kth user

${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; if\; sub</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; carrier\; n\; is\; assigned\; to\; user\; k</span>}<span\; class="notranslate">\; ,</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; otherwise</span>}<span\; class="notranslate">\; .</span>\end{array}\right.$

The base station regards all relay stations as a whole relay station. On the premise of meeting the minimum transmission rate requirements of different service types and maximizing system throughput as a criterion, the base station allocates subcarrier resources and power resources to direct transmission users and relay stations. The specific steps are as follows:

①Initialization: Set the transmit power of the access station (base station) to be divided equally on each subcarrier, and there is $p_{\mathrm{BS}}^m(i,\mathrm{no})=\frac{1}{N}{P}_{\max }^{\mathrm{BS}},$ Let n=1, and have ${\mathrm{PRI}}_{\mathrm{no},k}^m=c_{\mathrm{no},k}^m,\&ForAll;k;$

②If n≤N, find out the user k, and set $a_{\mathrm{no},k}^m=1;$ Otherwise, skip to step ⑤;

③ update ${\mathrm{\&delta;}}_{\mathrm{no}+1,k}^m=R_k^m-{\mathrm{\&Sigma;}}_{j=1}^{\mathrm{no}}{a}_{j,k}^m{c}_{j,k}^m,$ like ${\mathrm{\&delta;}}_{\mathrm{no}+1,k}^m<0,$ order ${\mathrm{\&delta;}}_{\mathrm{no}+1,k}^m=0;$

若 ${\mathrm{PRI}}_{n+1,k}^m=0,$

令 ${\mathrm{PRI}}_{n+1,k}^m=c_{n,k}^m,$

且n＝n+1，返回第②步；④ update ${\mathrm{PRI}}_{\mathrm{no}+1,k}^m=c_{\mathrm{no}+1,k}^m\&Center\; Dot;({\mathrm{\&delta;}}_{\mathrm{no}+1,k}^m/R_k^m),$

like ${\mathrm{PRI}}_{\mathrm{no}+1,k}^m=0,$

make ${\mathrm{PRI}}_{\mathrm{no}+1,k}^m=c_{\mathrm{no},k}^m,$

And n=n+1, return to step ②;

⑤ Allocate power to the nth subcarrier of the kth user

${\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; Ba</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&mu;</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

in, $Q_k^m(1,\mathrm{no})=\frac{G_k^m(1,\mathrm{no}){\mathrm{\&Gamma;}}_k^m}{I_k^m(1,\mathrm{no})+{\mathrm{\&sigma;}}^2},$ μ _k is to maximize the system capacity and satisfy the constraints $\underset{\mathrm{no}=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_k^m(1,\mathrm{no})a_{\mathrm{no},k}=P_{\max }^{\mathrm{BS}}\frac{{\mathrm{\&Sigma;}}_{\mathrm{no}=1}^N{a}_{\mathrm{no},k}}{N}$ The Lagrange multiplier factor of .

The above steps ①～⑤ realize that the base station meets the minimum transmission rate requirements of different service types as the premise, maximizes the system throughput as the criterion, and allocates system resources to the direct transmission users (step 3) and the overall relay station (step 3). 4).

预估各个中继站为支持第二跳链路的传输所需要的子载波数量，并将第三步分配后，分配给整体中继站的子载波资源按照预估的结果进行资源预分配(步骤5)。The fourth step, the base station according to the average rate information fed back by the relay station

Estimate the number of subcarriers required by each relay station to support the transmission of the second hop link, and after the third step of allocation, the subcarrier resources allocated to the overall relay station are pre-allocated according to the estimated result (step 5).

Let N _r be the number of subcarriers allocated to all relay stations after the third step is completed, and R _j be the average rate information fed back by the base station according to each relay station The estimated transmission rate required by the relay to support the transmission of the second hop link, j=1, . . . , J, J is the number of relay stations placed in each cell. Then the number of subcarriers N _{r, j} that each relay station needs to allocate is

Due to the lack of accurate channel information feedback, there must be a certain deviation in the estimation made by the base station in the fourth step, but its fundamental purpose is to allocate the first hop as accurately as possible according to the needs of relay users with less feedback resources, paving the way for the second allocation of relay stations.

Step 5. According to the transmission rate of the relay user on the first hop link and the channel state information of the second hop link fed back by the relay user, the relay station adjusts the subcarrier allocation and the power on each subcarrier to allocate the second hop link. Hop link resources to achieve two-hop rate balance. Among them, the schematic diagram of the two-hop equalization of the cellular relay network is shown in Figure 6, and its fundamental purpose is to make the two-hop rates of the same relay user as equal as possible.

$\underset{{\mathrm{\&xi;}}_{\mathrm{no},k}^m}{\min }|R_{k_r}^m\left(1\right)-\underset{\mathrm{no}\&Element;N_r}{\mathrm{\&Sigma;}}{a}_{\mathrm{no},k_r}^m{c}_{\mathrm{no},k_r}^m|,$ ${\&ForAll;k}_r\&Element;K_r^m$

$\mathrm{the\; s}.t.\underset{k\&Element;K_r^m}{\mathrm{\&Sigma;}}{a}_{\mathrm{no},k_r}^m=1,$ $\&ForAll;\mathrm{no}\&Element;N_r$

是中继用户k_r在第一跳链路上的传输速率，是通过中继站的资源分配之后，中继用户k_r在第二跳链路上的传输速率。两跳均衡可以通过两跳采用不用的子载波，或者不同数量的子载波实现，这样不仅可提高资源利用率，还能进一步增强系统的吞吐量。in,

is the transmission rate of the relay user k _r on the first-hop link, is the transmission rate of the relay user k _r on the second hop link after resource allocation by the relay station. Two-hop equalization can be realized by using unused subcarriers or different numbers of subcarriers in two hops, which can not only improve resource utilization, but also further enhance system throughput.

Based on the above two-hop balance criterion, the specific steps of the second resource allocation performed by the relay station are as follows:

①Initialization: Set the transmit power of the access station (relay station) to be equally divided on each subcarrier, and for the jth relay station, there is $p_{\mathrm{RN},j}^m(i,\mathrm{no})=\frac{1}{N_{r,j}}{P}_{\max }^{\mathrm{RN}},$ Let n=1, and have ${\mathrm{PRI}}_{\mathrm{no},k_r}^m=c_{\mathrm{no},k_r}^m,\&ForAll;k_r;$

的用户k_r，并设 $a_{n,k_r}^m=1;$ 否则，跳转第⑤步；②If n≤N _r,j , find out the

user k _r , and set $a_{\mathrm{no},k_r}^m=1;$ Otherwise, skip to step ⑤;

③ update ${\mathrm{\&delta;}}_{\mathrm{no}+1,k_r}^m=R_{k_r}^m-{\mathrm{\&Sigma;}}_{h=1}^{\mathrm{no}}{a}_{h,k_r}^m{c}_{h,k_r}^m,$ like ${\mathrm{\&delta;}}_{\mathrm{no}+1,k_r}^m<0,$ order ${\mathrm{\&delta;}}_{\mathrm{no}+1,k_r}^m=0;$

若 ${\mathrm{PRI}}_{n+1,k_r}^m=0,$

令 ${\mathrm{PRI}}_{n+1,k_r}^m=c_{n,k_r}^m,$

且n＝n+1，返回第②步；④ update ${\mathrm{PRI}}_{\mathrm{no}+1,k_r}^m=c_{\mathrm{no}+1,k_r}^m\&Center\; Dot;({\mathrm{\&delta;}}_{\mathrm{no}+1,k_r}^m/R_{k_r}^m),$

like ${\mathrm{PRI}}_{\mathrm{no}+1,k_r}^m=0,$

make ${\mathrm{PRI}}_{\mathrm{no}+1,k_r}^m=c_{\mathrm{no},k_r}^m,$

And n=n+1, return to step ②;

⑤ Allocate power to the k _rth user on the nth subcarrier of the second hop link

${\mathrm{<span\; class="notranslate">\; p</span>}}_{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; NR</span>}}_{\mathrm{<span\; class="notranslate">\; kr</span>}}^{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}^{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

in $Q_{\mathrm{no}}=Q_{k_r}^m(2,\mathrm{no})=\frac{G_{k_r}^m(2,\mathrm{no}){\mathrm{\&Gamma;}}_{k_r}^m}{I_{k_r}^m(2,\mathrm{no})+{\mathrm{\&sigma;}}^2},$ n=1, . . . , Nr _,j .

⑥ Fine-tune the above power $p_{k_r}^m(2,\mathrm{no})=p_{k_r}^m(2,\mathrm{no})\&PlusMinus;\mathrm{\&Delta;P},$ I'm satisfied $|R_{k_r}^m\left(1\right)-\underset{\mathrm{no}=1}{\overset{N_r}{\mathrm{\&Sigma;}}}{a}_{\mathrm{no},k_r}^m{c}_{\mathrm{no},k_r}^m|<\mathrm{\&zeta;},$ That is, the constraints of the two-hop rate balance.

Among them, ΔP is the adjusted power step size, and ζ is the set rate difference threshold satisfying two-hop equalization.

The above steps ① to ⑥ realize that the relay station allocates the resources assigned to it by the base station through the fourth step according to the channel state information of the second hop link of the relay user and the two-hop rate balance as a criterion, and then effectively allocates them to the relay user.

Next, the superiority of the semi-distributed resource allocation method of the present invention will be verified according to a specific resource allocation embodiment.

Assume that in this embodiment, the system consists of 7 cells, one base station is placed in the center of each cell, and 6 relay stations are evenly placed in each cell at 2/3 of the cell radius, and the maximum downlink transmission power of the base station BS is 20W , the maximum downlink transmission power of the relay station RS is 2.5W, the number of subcarriers is 128, the subcarrier bandwidth is 160kHz, and the carrier frequency is 3.95GHz. According to the three resource allocation methods shown in Figure 2a-2c, in the centralized resource allocation method, the base station can obtain the channel state information of all user links; in the distributed resource allocation method, the relay station does not need to feedback the relay User second hop link channel state information; in the semi-distributed resource allocation method proposed by the present invention, the relay station feeds back the average rate of the second hop of the relay user weighted by equal weight to the base station, which is a specific embodiment, comparing the above Pros and cons of the three methods.

Through simulation verification, it can be seen that the semi-distributed method of the present invention has improved the rate of relay users to a certain extent, and at the same time the rate of direct transmission users has also been greatly improved. The satisfaction rate performance is very close to that of the centralized method, and the satisfaction rate is compared with the distributed strategy. The improvement is larger. To sum up, the semi-distributed resource allocation method proposed by the present invention is a solution that takes both system throughput and user satisfaction into consideration, reduces system overhead, and makes resource utilization more reasonable.

The semi-distributed resource allocation method of the present invention makes full use of the resource management function of the network element of the relay station, which not only reduces the feedback overhead and algorithm complexity, but also effectively improves the user satisfaction rate of the network and ensures the communication services of users in the mobile environment quality, enhances the system throughput, makes efficient use of limited wireless resources, and has strong practicability.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

FIG. 7 is a schematic structural diagram of an embodiment of the semi-distributed resource allocation system of the present invention. The present invention includes a first channel state acquisition module 71 , a first resource allocation module 72 , a second channel state acquisition module 81 and a second resource allocation module 82 . Wherein, the first channel state acquisition module 71 is set in the base station BS 7, and is used to obtain the channel state information of the direct transmission link fed back by the direct transmission user d-MS 6, and the channel state of the first hop link fed back by the relay station RS 8 information and the average rate information of the second hop link estimated by the relay station RS 8.

The first resource allocation module 72 is set in the base station BS 7, and is used to allocate resources to the relay station RS 8 and the direct transmission user d according to the channel state information of the direct transmission link, the channel state information and the average rate information of the first hop link -MS6.

The second channel state acquisition module 81 is set in the relay station RS 8, and is used to obtain the channel state information of the second hop link fed back by the relay user r-MS 9. The second resource allocation module 82 is set in the relay station RS 8, and is used to redistribute the resources allocated to the relay station RS 8 to the relay user r-MS 9 according to the channel state information of the second hop link.

As shown in FIG. 8 , it is a schematic structural diagram of another embodiment of the semi-distributed resource allocation system of the present invention. Compared with the previous embodiment, this embodiment also includes an average rate estimation module 83, which is set in the relay station RS 8 and is used to estimate the average rate of the second hop link according to the channel state information of the second hop link. rate information.

In the above embodiment, the first resource allocation module 72 may specifically include: an overall relay station allocation unit, configured to regard all relay stations as an overall relay station, and the base station allocates system resources to the direct transmission users and the overall relay station; An estimating unit, configured to estimate the number of subcarriers required by each relay station to support the transmission of the second hop link; an individual relay station allocation unit, configured to allocate the resources allocated to the overall relay station according to the estimated subcarriers The number of carriers is allocated proportionally to each relay station.

The second resource allocation module 82 specifically includes: a subcarrier adjustment unit, configured to adjust the subcarrier according to the transmission rate of the relay user on the first hop link and according to the channel state information of the second hop link fed back by the relay user. Carrier allocation and the power on each subcarrier are used to allocate the resources of the second hop link to achieve two-hop rate equalization.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: the present invention can still be Modifications to the specific implementation of the invention or equivalent replacement of some technical features; without departing from the spirit of the technical solution of the present invention, should be included in the scope of the technical solution claimed in the present invention.

Claims (10)

1. A semi-distributed resource allocation method comprises the following steps:

the base station obtains channel state information of a direct transmission link fed back by a direct transmission user, channel state information of a first hop link fed back by the relay station and average rate information of a second hop link estimated by the relay station;

the base station allocates resources to the relay station and the direct transmission user according to the channel state information of the direct transmission link, the channel state information of the first hop link and the average rate information;

and the relay station reallocates the resources allocated to the relay station to the relay user according to the channel state information of the second hop link fed back by the relay user.

2. The semi-distributed resource allocation method according to claim 1, wherein before the relay station feeds back the average rate information of the second hop link, further comprising the steps of:

and the relay station receives channel state information of a second hop link fed back by a relay user, and estimates average rate information of the second hop link according to the channel state information of the second hop link.

3. The semi-distributed resource allocation method according to claim 2, wherein the operation of predicting the average rate information of the second hop link specifically comprises:

and the relay station carries out weighting processing on the channel information of the relay user on each subcarrier of the second hop link and estimates the average rate information of the second hop link.

4. The semi-distributed resource allocation method according to claim 1, wherein the operation of the base station allocating resources to the relay station and the direct transmission user according to the channel state information of the direct transmission link, the channel state information of the first hop link, and the average rate information specifically includes:

all relay stations are regarded as integral relay stations, and the base station allocates system resources to the direct transmission users and the integral relay stations;

and according to the average rate information of the second hop link, the base station predicts the number of subcarriers required by each relay station for supporting the transmission of the second hop link, and distributes the resources distributed to the whole relay station to each relay station in proportion according to the predicted number of the subcarriers.

5. The semi-distributed resource allocation method according to claim 4, wherein the operation of allocating system resources to the direct transmission user and the overall relay station is specifically:

and the base station allocates resources to the direct transmission users and the whole relay station on the premise of meeting the minimum transmission rate requirements of different service types and maximizing the system throughput.

6. The semi-distributed resource allocation method according to any one of claims 1 to 5, wherein the operation of reallocating the resources allocated to the relay station to the relay user is specifically:

and the relay station adjusts the subcarrier allocation and the power on each subcarrier to allocate the resources of the second hop link according to the transmission rate of the relay user in the first hop link and the channel state information of the second hop link fed back by the relay user so as to realize the two-hop rate balance.

7. A semi-distributed resource allocation system, comprising:

the first channel state acquisition module is arranged in the base station and used for acquiring channel state information of a direct transmission link fed back by a direct transmission user, channel state information of a first hop link fed back by the relay station and average rate information of a second hop link estimated by the relay station;

the first resource allocation module is arranged in the base station and used for allocating resources to the relay station and the direct transmission user according to the channel state information of the direct transmission link, the channel state information of the first hop link and the average rate information;

the second channel state acquisition module is arranged in the relay station and used for acquiring channel state information of a second hop link fed back by a relay user;

and the second resource allocation module is arranged in the relay station and used for reallocating the resources allocated to the relay station to the relay user according to the channel state information of the second hop link.

8. The semi-distributed resource allocation system according to claim 7, further comprising an average rate estimation module, disposed in the relay station, for estimating the average rate information of the second hop link according to the channel state information of the second hop link.

9. The semi-distributed resource allocation system according to claim 7, wherein said first resource allocation module specifically comprises:

a relay station overall allocation unit, configured to regard all relay stations as an overall relay station, where the base station allocates system resources to the direct transfer user and the overall relay station;

the subcarrier estimating unit is used for estimating the number of subcarriers required by each relay station for supporting the transmission of the second hop link;

and the relay station individual allocation unit is used for allocating the resources allocated to the whole relay station to each relay station in proportion according to the estimated subcarrier number.

10. The semi-distributed resource allocation system according to claim 9, wherein the second resource allocation module specifically comprises:

and the subcarrier adjusting unit is used for adjusting subcarrier allocation and power on each subcarrier to allocate resources of the second hop link according to the transmission rate of the relay user in the first hop link and the channel state information of the second hop link fed back by the relay user so as to realize two-hop rate balance.

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