CN101754378A - Base station and method for distributing radio resource - Google Patents

Abstract

The invention discloses a base station and method for distributing radio resource, comprising a state obtaining device, which is configured as signal channel state when a plurality of users occupy a plurality of radio resource units; a calculating device, which is configured as the device for estimating the throughput when the user occupies the radio recourse unit and calculating the ratio of the throughput and the sum of the throughputs when the user occupies the plurality of radio resource units according to the obtained signal channel state, aiming at each radio resource unit; and a choosing device, which is configured as the device for choosing one of the plurality of users and distributing the radio resource units to the chosen user according to the ratio of the plurality of users, aiming at each radio resource unit.

Description

Base station and method for allocating radio resources therein

technical field

The invention relates to wireless communication technology, in particular to resource allocation and multi-user scheduling in a multi-user environment in a wireless communication system.

Background technique

So far, the wireless communication system has obtained great development. The original second-generation mobile communication system GSM has continuously evolved to general radio packet service GPRS, EDGE with improved data rate and other technologies, which has greatly improved the data transmission capacity of the system. Third-generation mobile communication systems with higher transmission rates, such as wideband code division multiple access WCDMA, CDMA2000 and other technologies, have also been deployed in many countries and regions around the world and have begun to be put into commercial use. Along with the development of cellular communication technology, other wireless access technologies such as wireless local area network WLAN and microwave access WiMAX have also developed rapidly. In addition, projects such as IEEE802.16m technology for the fourth-generation mobile communication system, the third-generation partnership project evolution technology 3GPP LTE, and the third-generation partnership project evolution technology enhancement 3GPP LTE+ have also begun to enter the research and development stage.

New wireless transmission technologies and network architectures pose new challenges to radio resource management. Wireless resource allocation in a multi-user environment is an important content of wireless resource management. Its ultimate purpose is to allocate the resources of each wireless access user and coordinate the access of each wireless user under a certain criterion, so that the wireless resources can be used more effectively.

In wireless communication systems, commonly used dynamic resource allocation schemes are mainly: maximum carrier-to-interference ratio scheduling criterion (Max C/I), proportional fair scheduling criterion (PF, Proportional Fair) and round robin scheduling criterion (RR, Round Robin). The goal of the Max C/I scheme is to maximize the system throughput. Since only the users with the best channel quality are considered, this scheduling scheme cannot guarantee the data transmission requirements of the cell edge users, that is, the users with poor channel conditions, and thus cannot guarantee the fairness of the system. The goal of the RR scheme is system fairness. Since the RR scheme does not consider the user's channel conditions, it cannot make full use of the multi-user diversity gain brought about by the time-varying characteristics of the wireless channel. On the one hand, the PF scheme makes full use of the time-varying characteristics of user channels, and on the other hand, it ensures a better balance between multi-user diversity and fairness in the system. It has gradually become a more commonly used multi-user scheduling and resource allocation algorithm in wireless communication systems. However, the computational complexity of the PF scheme is relatively high, which increases the implementation cost, especially in wireless communication systems based on multiple-input multiple-output (MIMO) technology.

References for the present invention are listed below and are hereby incorporated by reference as if fully described in this specification.

1. [Patent Document 1]: WAN LEI and LUI YIN, SCHEDULINGAND LINKADAPTATION IN WIRELESS TELECOMMUNICATIONS SYSTEMS (WO2008028507);

2. [Patent Document 2]: FUJITA HIROSHI and YOSHIDA MAKOTO, SCHEDULER AND WIRELESS BASE STATION APPARATUS WITHTHE SCHEDULER, AND SCHEDULING METHOD (JP2008022135);

3. [Patent Document 3]: MCBEATH SEAN M and BI HAO, SCHEDULING INWIRELESS COMMUNICATION SYSTEMS (WO2007117757);

4. [Patent Document 4]: CLASSON BRIAN K and BI HAO, METHOD ANDAPPARATUS FOR SCHEDULING FREQUENCY SELECTIVE ANDFREQUENCY DIVERSE ALLOCATIONS IN MOBILECOMMUNICATIONS SYSTEMS (WO2007082141);

5. [Patent Document 5]: KAZUHITO TAKANO and MICHIAKI FUKUI, SCHEDULER, BASE STATION, AND SCHEDULING METHOD (CN1934886);

6. [Patent Document 6]: SUBRAMANIAN VIJAY G and AGRAWALRAJEEV, METHOD AND APPARATUS FOR RESOURCEALLOCATION AND SCHEDULING (JP2005176344)

7. [Non-Patent Document 1]: R.KNOPP, P.A.HUMBLER, "INFORMATIONCAPACITY AND POWER CONTROL IN SINGLE CELL MULTIUSER COMMUNICATIONS," IN PROC.IEEE ICC'95, JUNE.1995;

8. [Non-Patent Document 2]: A.JALALI, R.PADOVANI and R.PANKAJ, "DATA THROUHGPUT OF CDMA-HDR A HIGH EFFICIENCY-HIGHDATA RATE PERSONAL COMMUNICATION WIRELESS SYSTEM", IN PROC.IEEE VTC.2000, PP. 1854-1858.

Contents of the invention

The object of the present invention is to provide a base station in a wireless communication system and a method for allocating wireless resources therein, so as to at least partly overcome the deficiencies in the prior art.

An embodiment of the present invention provides a base station, including: a state obtaining device configured to obtain channel states when multiple users occupy multiple wireless resource units; a computing device configured to, for each wireless resource unit, according to The obtained channel state estimates the throughput when each user occupies the wireless resource unit, and calculates the ratio of the throughput to the sum of the throughput when the user occupies the plurality of wireless resource units; and selecting means , configured to, for each radio resource unit, select one of the plurality of users according to the ratio of the plurality of users, so as to allocate the radio resource unit to the selected user.

An embodiment of the present invention provides a method for allocating wireless resources in a base station, including: obtaining channel states when multiple users occupy multiple wireless resource units; for each wireless resource unit, estimating each the throughput when a user occupies the radio resource unit; calculate the ratio of the throughput to the sum of the throughput when the user occupies the plurality of radio resource units; and for each radio resource unit, according to the The ratio of a plurality of users, one of the plurality of users is selected to allocate the radio resource unit to the selected user.

Description of drawings

The above and other objects, features and advantages of the present invention will be more easily understood with reference to the following description of the embodiments of the present invention in conjunction with the accompanying drawings. The components in the figures are not drawn to scale, merely illustrating the principles of the invention. For ease of illustration and description of some parts of the invention, corresponding parts in the drawings may be exaggerated, ie made larger relative to other parts in an exemplary device actually manufactured in accordance with the invention. In the drawings, the same or corresponding technical features or components will be indicated by the same or corresponding reference numerals.

The block diagram of Figure 1 schematically shows the general structure of a base station in a multi-user wireless communication system;

The schematic diagram of Fig. 2 shows the configuration of radio resource units in the base station of Orthogonal Frequency Division Multiple Access OFDMA system;

The block diagram of Fig. 3 shows the structure of the resource allocation module in the base station according to the embodiment of the present invention;

The flowchart of FIG. 4 shows a radio resource allocation method according to an embodiment of the present invention;

The flowchart of Fig. 5 shows in detail the process of obtaining the channel state in the method of Fig. 4;

The block diagram of Fig. 6 shows the structure of the resource allocation module in the base station according to another preferred embodiment of the present invention;

The flowchart of FIG. 7 shows a method for allocating radio resources according to a preferred embodiment of the present invention;

The flow chart of FIG. 8 shows in detail the process of adjusting weights in the method of FIG. 7 .

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings. Elements and features described in one drawing or one embodiment of the present invention may be combined with elements and features shown in one or more other drawings or embodiments. It should be noted that representation and description of components and processes that are not related to the present invention and known to those of ordinary skill in the art are omitted from the drawings and descriptions for the purpose of clarity.

In the description and drawings, specific embodiments of the invention are disclosed in detail, indicating the manner in which the principles of the invention may be employed. It should be understood that the invention is not thereby limited in scope. The invention embraces many changes, modifications and equivalents within the spirit and scope of the appended claims.

Features described and/or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with, or instead of features in other embodiments .

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, element, step or component, but does not exclude the presence or addition of one or more other features, elements, steps or components.

In a wireless communication system, wireless resources are allocated to users in units of wireless resource units. A radio resource unit is defined by a series of basic physical transmission parameters. Different multiple access modes correspond to different types of parameters. For example, in a frequency division multiple access FDMA system, a wireless resource unit is equivalent to a section of available wireless frequency; in a time division multiple access TDMA system, a wireless resource unit is equivalent to a time slot in a working frequency point; in a space division multiple access In the SDMA system, the wireless resource unit is equivalent to the spatial direction in the working frequency point; in the code division multiple access CDMA system, the wireless resource unit is equivalent to the channel code in the working frequency point; in the orthogonal frequency division multiple access OFDMA system In , the radio resource unit is equivalent to the subcarrier and transmission time interval in the working frequency point. In order to improve the throughput and quality of service of the wireless communication system, the wireless communication system mostly adopts the MIMO technology of multi-antenna transmission at the transmitter and multi-antenna reception at the receiver, such as 3GPP LTE and IEEE 802.16m systems have decided to use MIMO+OFDMA as the physical layer transmission technology. Essentially, the MIMO+OFDMA system is a highly efficient combination of statistical space-division multiplexing, frequency-division multiplexing, and time-division multiplexing. In this system, the radio resource unit is equivalent to the combination of the transmission channel (space), subcarrier (frequency) and transmission time interval (time) in the working frequency point.

Fig. 2 is a schematic diagram showing the configuration of radio resource units in a base station of an Orthogonal Frequency Division Multiple Access (OFDMA) system.

As shown in FIG. 2 , radio resource units are divided according to subcarriers in the frequency direction and time slots in the time direction. For example, radio resource unit R _1,1 corresponds to the first subcarrier or the first subcarrier group in the first time slot, and radio resource unit R _1,6 corresponds to the first subcarrier in the sixth time slot subcarrier or the first subcarrier group, radio resource unit R _{10, 1} corresponds to the 10th subcarrier or the 10th subcarrier group in the first time slot, and radio resource unit R _{10, 6} corresponds to the 6th time slot the 10th subcarrier or group of 10th subcarriers in the slot, and so on.

In a wireless communication system, the main purpose of wireless resource allocation in a multi-user environment is to allocate system-specific wireless resource units—space, time, and frequency resources of the system—to specific users according to the real-time status of the channel and the real-time requirements of users. In order to achieve a predetermined balance between system resource utilization efficiency and multi-user fairness.

The block diagram of Fig. 1 schematically shows the general structure of a base station in a multi-user wireless communication system.

As shown in FIG. 1, there are multiple users 1 to K communicating with the base station. The base station includes data buffers 110-1 to 110-K, which are respectively used to buffer downlink transmission data for user 1 to user K. The base station also includes a resource allocation module 120 , a coding and modulation module 130 and a transmitting module 140 . Regardless of the specific physical layer technology used in the wireless communication system, physical resources can be divided into logical wireless resource units according to certain rules, such as time slots in TDMA systems, frequency points in FDMA systems, codewords in CDMA systems, etc. wait. When the base station decides to allocate wireless resources, the resource allocation module 120 is responsible for allocating each wireless resource unit to multiple users 1 to K, and combining the data buffered in the data buffers 110-1 to 110-K with the allocated wireless resource units Correlate and transmit to coding and modulation module 130. The encoding and modulation module 130 encodes and modulates data onto the associated radio resource units. The transmitting module 140 transmits the modulated data through the physical resource corresponding to the associated radio resource unit. Alternatively, the data is received by a receiving module (not shown), and demodulated and decoded by a decoding and demodulation module (not shown). Data identifying the corresponding user based on resource allocation.

The module diagram in Fig. 3 shows the structure of the resource allocation module in the base station according to the embodiment of the present invention.

As shown in FIG. 3 , the resource allocation module includes state obtaining means 301 , calculating means 302 and selecting means 303 .

The state obtaining means 301 obtains channel states when multiple users 1 to K occupy multiple radio resource units. The base station has S radio resource units. For example, the status obtaining means 301 can make the base station send a status query to each user's terminal through a control channel, and send pilots on the S radio resource units. In response to the status query, each user's terminal can perform corresponding channel estimation according to the pilot frequency on each radio resource unit. Channel measurement using the pilot frequency of the radio resource unit can obtain the channel state data r _i (j)={h _i (j), n _i (j)}, where i=1, 2, ..., K, j= 1, 2, ..., S, h _i (j) is the channel impulse response of the jth wireless resource unit of user i, and n _i (j) is the noise power of the jth wireless resource unit of user i. Each user's terminal reports the measured channel state of each radio resource unit to the base station, that is, the state obtaining means 301 . The channel status can be obtained by using the existing status query mechanism.

For each radio resource unit, the computing device 302 estimates the throughput of each user when occupying the radio resource unit according to the obtained channel state, and calculates the sum of the throughput and the throughput when the user occupies multiple radio resource units ratio.

For example, throughput can be calculated according to:

${\mathrm{<span\; class="notranslate">\; MI</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Where MI _i (j) is the throughput when user i occupies the jth radio resource unit. This throughput is also called the mutual information of user i with respect to radio resource unit j.

The above ratios can be calculated according to the following formula:

${\mathrm{<span\; class="notranslate">\; MIR</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; MI</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}{\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; S</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; MI</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Where MIR _i (j) is the ratio of the throughput MI _i (j) when user i occupies the jth radio resource unit to the sum of throughput when user i occupies multiple radio resource units 1 to S. This ratio is also called the mutual information ratio of user i relative to radio resource unit j. After the above calculation is completed, each radio resource unit j obtains a K-dimensional mutual information ratio vector {MIR ₁ (j), MIR ₂ (j), . . . , MIR _K (j)}. There are S vectors in total, corresponding to S radio resource units respectively.

For each radio resource unit, the selecting means 303 selects one of the users according to the ratio of multiple users 1 to K, so as to allocate the radio resource unit to the selected user. Users may be selected according to various selection strategies. For example, for each radio resource unit, a ratio can be randomly selected from several larger ratios of its vectors (i.e. users), so that the radio resource unit can be assigned to the user corresponding to the ratio, or it can be based on, for example, the quality of service Agreed other factors from which users are selected to prioritize guaranteed service. Preferably, the user with the largest ratio can be selected. For each radio resource unit, the selection by the selecting means 303 causes the selected user to receive or send data on the radio resource unit. Correspondingly, the coding and modulation module 130 selects a coding and modulation scheme MCS according to system requirements, and transmits data through the transmitting module 140 after coding and modulation. Alternatively, the data is received by a receiving module (not shown), and demodulated and decoded by a decoding and demodulation module (not shown). Data identifying the corresponding user based on resource allocation.

Compared with the PF scheme, the embodiments of the present invention have better performance.

In the case of a single radio resource unit, N users of the system compete for only one radio resource unit. For example, in a single-carrier TDMA system, N users of the system compete for the next time slot that can be scheduled. The user selection criteria for the PF scheme are:

$\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; max</span>}}\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1,2</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}$

where U represents the set of users, r _i (t) is the real-time data transmission rate of user i at time t, m(t) is the transmission user selected at time t, and R _i (t) is the average transmission rate of user i at time t-1 Bit rate, N is the overall number of users, the update formula of the average transmission bit rate R _i (t) is expressed as:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}$

where T is the length of the averaging time window.

In the MIMO-OFDMA system, the radio resource unit of the system is the combination of space, time and frequency resources of the system. Therefore, data of multiple users is transmitted on different radio resource units. This makes it necessary for the scheduling algorithm to select multiple users at the same time and allocate corresponding radio resource units to the multiple users. In this case, the PF scheduling criterion can be expressed as

$\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arg</span>}\mathrm{<span\; class="notranslate">\; max</span>}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&Element;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{\mathrm{<span\; class="notranslate">\; \&Pi;</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&Element;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>$

Among them, r _{i, k} (t) is the data transmission rate of user i on the radio resource unit k of the system at time t, R _i (t) is the average data transmission rate of user i at time t-1, and T is the average time The length of the window, C _i is the set of carriers allocated to user i, and U is the set of users. The update formula of R _i (t) can be expressed as:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&Element;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}$

It can be seen that in the MIMO-OFDMA system, at each data transmission moment, the allocation of radio resource units needs to be considered. For a communication system with N users and S radio resource units, it is necessary to perform N ^S times of comparisons. Obtaining the optimal radio resource unit allocation scheme requires a very large computational complexity, which is difficult to implement in an actual system. However, in the embodiment of the present invention, only N×S comparisons are required. In addition, because PF scheduling uses the average transmission rate to represent the fairness among users, although it has better long-term fairness, it cannot guarantee the short-term fairness among users. However, in the embodiment of the present invention, short-term fairness among users can be guaranteed because the allocation is performed based on the obtained channel state.

The flow chart in Fig. 4 shows a radio resource allocation method in a base station according to an embodiment of the present invention.

As shown in FIG. 4 , at each resource allocation opportunity, the method starts from step 400 . In step 402, channel states when multiple users 1 to K occupy multiple (S) wireless resource units are obtained.

The flowchart of FIG. 5 shows the process of step 402 in detail.

As shown in FIG. 5 , the process begins at step 500 . In step 502, a status query is sent to each user's terminal through a control channel, and a pilot is sent on the S radio resource units. In step 504, in response to the status query, each user's terminal performs corresponding channel estimation according to the pilot frequency on each radio resource unit. Channel measurement using the pilot frequency of the radio resource unit can obtain the channel state data r _i (j)={h _i (j), n _i (j)}, where i=1, 2, ..., K, j= 1, 2, ..., S, h _i (j) is the channel impulse response of the jth wireless resource unit of user i, and n _i (j) is the noise power of the jth wireless resource unit of user i. In step 506, each user's terminal reports the measured channel state of each radio resource unit to the base station. The channel status can be obtained by using the existing status query mechanism. The process ends at step 508 .

Returning to Fig. 4, in step 404, for each radio resource unit, the throughput of each user when occupying the radio resource unit is estimated according to the obtained channel state. For example, throughput can be calculated according to formula (1).

In step 406, the ratio of the throughput to the sum of the throughput when the user occupies multiple radio resource units is calculated. The above ratio can be calculated according to formula (2). After the above calculation is completed, each radio resource unit j obtains a K-dimensional mutual information ratio vector {MIR ₁ (j), MIR ₂ (j), . . . , MIR _K (j)}. There are S vectors in total, corresponding to S radio resource units respectively.

In step 408, for each radio resource unit, one of the users is selected according to the ratio of multiple users 1 to K, so as to allocate the radio resource unit to the selected user. Users may be selected according to various selection strategies. For example, for each radio resource unit, a ratio can be randomly selected from several larger ratios (i.e., users) of its vector, so that the radio resource unit can be assigned to the user corresponding to the ratio, or can be allocated according to, for example, the quality of service Agreed other factors from which users are selected to prioritize guaranteed service. Preferably, the user with the largest ratio can be selected.

In step 410, each radio resource unit is allocated to the selected user. For each radio resource unit, the above selection causes the selected user to send data on the radio resource unit. Correspondingly, the base station selects a modulation and coding scheme MCS according to system requirements, and transmits data after coding and modulation. The method ends at step 412 .

In a multi-user wireless communication system, the system throughput and the system's multi-user fairness are a pair of contradictions. When expanding the system throughput, the multi-user fairness of the system must be sacrificed; when the multi-user fairness of the system is satisfied, the system throughput is not the maximum possible throughput of the system. The balance between system throughput and system multi-user fairness usually depends on the upper layer control decisions of the system. Therefore, it is expected that the resource allocation scheme of the system can reflect this kind of balanced control.

The maximum carrier-to-interference ratio scheduling criterion (Max C/I) cannot satisfy the fairness of multiple users. Round Robin (RR, Round Robin) cannot make full use of the multi-user diversity of the system to improve the throughput of the system. The PF scheme achieves a certain degree of balance between the throughput and fairness of the system, but the scheme has no control means. When the system's decision-making requires to further improve the system throughput or further improve the multi-user fairness of the system, the PF scheme cannot be adjusted accordingly to reflect and fulfill the resource allocation requirements of the upper-layer decision-making.

In a preferred embodiment of the present invention, calculation means 302 and step 404 calculate throughput according to the following formula:

${\mathrm{<span\; class="notranslate">\; MI</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{<span\; class="notranslate">\; |</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Where MI _i (j) is the throughput when user i occupies the jth radio resource unit. α is a weight used to control the balance between system throughput and multi-user fairness. The weight α is governed by the control decision of the system. α is generally greater than 0. Preferably, α is greater than 0 and less than or equal to 100. The smaller α is, the higher priority is given to system throughput, and the larger α is, the higher priority is given to multi-user fairness. This throughput is also called the mutual information of user i with respect to radio resource unit j.

From equation (3), it can be seen that the throughput is calculated by applying a weight α to the signal power of the channel state. A preferred embodiment of the invention enables to choose a balance between system throughput and multi-user fairness by controlling the weight α.

The block diagram in Fig. 6 shows the construction of a resource allocation module in a base station according to another preferred embodiment of the present invention.

As shown in FIG. 6 , the resource allocation module includes state obtaining means 601 , calculating means 602 , selecting means 603 and weight adjusting means 604 .

The state obtaining means 601 and the selecting means 603 are respectively the same as the state obtaining means 301 and the selecting means 303 in FIG. 3 , and their detailed descriptions are omitted here. The computing device 602 is basically the same as the computing device 302 in FIG. 3 , but uses the formula (3) to calculate the throughput as described above, and also calculates the system throughput of the base station and the multi-user fairness of the base station.

The computing device 602 can calculate the system throughput according to the following formula:

$\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; K</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

是用户i的平均信息传输速率。in

is the average information transfer rate of user i.

Computing device 602 can calculate the multi-user fairness of the system according to the following formula:

$\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; max</span>}<span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; min</span>}<span\; class="notranslate">\; (</span>{\stackrel{<span\; class="notranslate">\; ~</span>}{\mathrm{<span\; class="notranslate">\; r</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Of course, system throughput and multi-user fairness can also be calculated according to other definitions of system throughput and multi-user fairness. For example, the sum of the time average throughput of each user of the base station may be used as the system throughput; the ratio of the time average throughput maximum value and the time average throughput minimum value of each user of the base station may be used as multi-user fairness.

和多用户公平性

输入到权重调整装置604。Computing device 602 will system throughput

and multi-user fairness

Input to the weight adjustment device 604.

Weight adjusting means 604 adjusts weights according to system throughput and multi-user fairness, so as to achieve a predetermined balance between system throughput and multi-user fairness. According to the characteristic that the smaller α is, the priority is given to system throughput, and the larger α is, the priority is given to multi-user fairness, and the type and degree of current system throughput and multi-user fairness deviating from a predetermined balance, the weight adjustment means 604 Decide how to adjust α to achieve a predetermined balance.

In an example, the weight adjustment unit 604 may compare the system throughput with the system throughput threshold, and compare the multi-user fairness with the multi-user fairness threshold. If the system throughput is greater than or equal to the system throughput threshold and the multi-user fairness is greater than or equal to the multi-user fairness threshold, the weight adjusting means 604 does not adjust the weight α. If the system throughput is less than the system throughput threshold and the multi-user fairness is greater than or equal to the multi-user fairness threshold, the weight adjusting means 604 decreases the weight α. If the system throughput is greater than or equal to the system throughput threshold and the multi-user fairness is less than the multi-user fairness threshold, the weight adjusting means 604 increases the weight α. If the system throughput is less than the system throughput threshold and the multiuser fairness is less than the multiuser fairness threshold, the balance target between system throughput and multiuser fairness can be changed.

In an optional embodiment, the weight adjustment unit 604 may compare the system throughput with a system throughput threshold. If the system throughput is less than the threshold, the weight adjusting means 604 decreases the weight α. In this embodiment, it is assumed that multi-user fairness satisfies the requirements. Accordingly, computing device 602 may not compute multi-user fairness.

In an optional embodiment, the weight adjustment unit 604 may compare the multi-user fairness with the multi-user fairness threshold. If the multi-user fairness is less than the threshold, the weight adjusting means 604 increases the weight α. In this embodiment, it is assumed that the system throughput meets the requirements. Accordingly, computing device 602 may not calculate system throughput.

The flowchart in Fig. 7 shows a radio resource allocation method according to another preferred embodiment of the present invention.

As shown in FIG. 7 , at each resource allocation opportunity, the method starts from step 700 . In step 702, the system throughput of the base station is calculated. The system throughput can be calculated according to formula (4). System throughput can also be calculated according to other definitions of system throughput. For example, the time average throughput of each user of the base station may be summed to be the system throughput.

In step 704, the multi-user fairness of the base station is calculated. The multi-user fairness of the system can be calculated according to formula (5). Multi-user fairness can also be calculated according to other definitions of multi-user fairness. For example, the ratio of the maximum value of the time average throughput and the minimum value of the time average throughput of each user of the base station may be used as the multi-user fairness.

In step 706, weights are adjusted according to system throughput and multi-user fairness, so as to achieve a predetermined balance between system throughput and multi-user fairness. How to adjust α can be decided according to the characteristic that the smaller α is, the higher priority is system throughput, and the larger α is, the higher priority is multi-user fairness, as well as the type and degree of deviation of current system throughput and multi-user fairness from the predetermined balance. , to achieve a predetermined balance.

The flow chart of FIG. 8 shows in detail the process of adjusting weights in the method of FIG. 7 .

As shown in FIG. 8 , the process begins at step 800 . In step 802, compare the system throughput with the system throughput threshold, and compare the multi-user fairness with the multi-user fairness threshold. If the system throughput is greater than or equal to the system throughput threshold and the multi-user fairness is greater than or equal to the multi-user fairness threshold, then the weight α is not adjusted, and the process ends in step 810 . Otherwise, in step 804, if the system throughput is less than the system throughput threshold and the multi-user fairness is greater than or equal to the multi-user fairness threshold, then reduce the weight α, and the process ends in step 810. Otherwise, at step 806, if the system throughput is greater than or equal to the system throughput threshold and the multi-user fairness is less than the multi-user fairness threshold, increase the weight α, and the process ends at step 810. Otherwise, the process ends at step 810, or alternatively, the balance target between system throughput and multi-user fairness can be changed.

In an optional embodiment, the system throughput may be compared with a system throughput threshold. If the system throughput is less than this threshold, the weight α is decreased. In this embodiment, it is assumed that multi-user fairness satisfies the requirements. Accordingly, step 704 can be omitted.

In an optional embodiment, multi-user fairness and multi-user fairness thresholds may be compared. If the multi-user fairness is less than this threshold, increase the weight α. In this embodiment, it is assumed that the system throughput meets the requirements. Accordingly, step 702 can be omitted.

Returning to FIG. 7 , steps 708 , 710 , 712 , 714 , and 716 are executed next. Steps 708 , 710 , 712 , 714 , and 716 are respectively the same as steps 402 , 404 , 406 , 408 , and 410 in FIG. 4 , so the description will not be repeated. The method ends at step 718 .

It should be noted that the present invention is not limited to a specific physical layer technology, and thus can be used in systems such as FDMA, TDMA, SDMA and OFDMA, and is not limited to the above-mentioned systems.

It should also be noted that although the present invention has been described in connection with downlink transmission in the previous embodiments, since the radio resource unit can be used for both downlink transmission and uplink transmission, the present invention is applicable to uplink and downlink transmission in a wireless communication system link, applicable to both time-division duplex TDD and frequency-division duplex FDD modes.

In the foregoing specification, the invention has been described with reference to specific embodiments. However, those of ordinary skill in the art understand that various modifications and changes can be made without departing from the scope of the present invention as defined in the claims.

Claims (14)

1. A base station, comprising: A state obtaining device configured to obtain channel states when multiple users occupy multiple radio resource units; The computing device is configured to, for each wireless resource unit, estimate the throughput when each user occupies the wireless resource unit according to the obtained channel state, and calculate the relationship between the throughput and the user occupying the multiple wireless resource units. The ratio of the sum of throughput in resource units; and The selection means is configured to, for each radio resource unit, select one of the plurality of users according to the ratio of the plurality of users, so as to allocate the radio resource unit to the selected user. 2. The base station according to claim 1, wherein the calculation means is further configured to calculate the throughput by applying a weight to the signal power of the channel state, the weight being greater than zero. 3. The base station according to claim 2, wherein the calculating means is further configured to calculate the system throughput of the base station, and/or the multi-user fairness of the base station, and the base station further comprises: The weight adjustment device is configured to adjust the weight according to the system throughput and/or multi-user fairness, so as to achieve a predetermined balance between system throughput and multi-user fairness. 4. The base station according to claim 3, wherein the computing device is further configured to sum the time-average throughput of each user of the base station as the system throughput. 5. The base station according to claim 3, wherein the calculation means is further configured to use the ratio of the maximum value of the time average throughput and the minimum value of the time average throughput of each user of the base station as the multi-user fairness . 6. The base station according to claim 3, wherein the weight adjusting means is further configured to decrease the weight when the system throughput is less than a predetermined value, and/or increase the weight when the multi-user fairness is lower than a predetermined value Big weight. 7. The base station according to any one of claims 1 to 6, wherein the selection means is further configured to select the user with the largest ratio from the plurality of users, so as to allocate the radio resource unit to the selected user. 8. A method for allocating wireless resources in a base station, comprising: Obtain channel states when multiple users occupy multiple radio resource units; For each radio resource unit, estimating the throughput of each user when occupying the radio resource unit according to the obtained channel state; calculating the ratio of the throughput to the sum of the throughput when the user occupies the plurality of radio resource units; and For each radio resource unit, one of the plurality of users is selected according to the ratio of the plurality of users, so as to allocate the radio resource unit to the selected user. 9. The method of claim 8, wherein said calculating comprises: The throughput is calculated by applying a weight to the signal power of the channel state, the weight being greater than zero. 10. The method of claim 9, wherein said calculating further comprises: Computing the system throughput of the base station, and/or the multi-user fairness of the base station, And the method also includes: The weights are adjusted according to the system throughput and/or multi-user fairness to achieve a predetermined balance of system throughput and multi-user fairness. 11. The method of claim 10, wherein the calculation of the system throughput comprises: The time average throughput of each user of the base station is summed to be the system throughput. 12. The method of claim 10, wherein the calculation of the multi-user fairness comprises: The ratio of the maximum value of the time average throughput and the minimum value of the time average throughput of each user of the base station is used as the multi-user fairness. 13. The method of claim 10, wherein said adjusting comprises: When the system throughput is less than a predetermined value, the weight is decreased, and/or when the multi-user fairness is lower than a predetermined value, the weight is increased. 14. The method of any one of claims 8 to 13, wherein said selecting comprises: Selecting the user with the largest ratio from the multiple users, so as to allocate the radio resource unit to the selected user.

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