WO2014183315A1

WO2014183315A1 - Distributed resource allocation method of mimo-ofdma wireless relay system

Info

Publication number: WO2014183315A1
Application number: PCT/CN2013/077573
Authority: WO
Inventors: 刘畅; 王江舟; 王向阳
Original assignee: 东南大学
Priority date: 2013-05-16
Filing date: 2013-06-20
Publication date: 2014-11-20
Also published as: CN103220116A

Abstract

A distributed resource allocation method of a MIMO-OFDMA wireless relay system. The method comprises steps: (1) initializing parameters of the MIMO-OFDMA wireless relay system; (2) a relay node calculating each value of a user terminal in a responsibility range thereof in sequence according to channel status information and a lagrange multiplier set by a base station, and sending calculation results of a subcarrier allocation value, an equivalent system power allocation value and throughput of delay-sensitive users to the base station; (3) the base station reporting a new lagrange multiplier result to the relay node; (4) the relay node determining whether the subcarrier and power allocation values achieve convergence and obtaining a final resource allocation result. The present invention is based on an optimized duality theory for multiple users and multiple carrier systems, considers multiple user weights, and uses a rate-adaptive distributed algorithm, which can reasonably allocate power and subcarrier resources, and can effectively reduce a computation amount of the base station.

Description

Distributed resource allocation method for MIM0-0FDMA wireless relay system

The invention belongs to the field of wireless communication technologies, and in particular relates to a distributed resource allocation method of a MIM0-0FDMA wireless relay system.

Background technique

The MIM0 multi-antenna technology benefits the multipath effect that originally caused interference, and can not only obtain spatial multiplexing gain, but also improve channel capacity, and also obtain spatial diversity gain, thereby improving channel reliability, but for frequency selection. Sexual decline is powerless. The 0FDMA technology not only utilizes the orthogonality of the spectrum to improve spectrum utilization, but also brings multi-user diversity gain and is effective against frequency selective fading, cell interference, and symbol interference. In addition, the LTE-A standard has explicitly adopted wireless relay technology to extend network coverage, reduce device power consumption, increase system capacity, and balance network load. The wireless relay system based on MIM0 multi-antenna and 0FDMA multiple access technology (referred to as MIMO-OFDMF) has become a recent in recent years due to the performance gains that can be combined with space resources and frequency resources, and the system performance is further improved by relay technology. The research hotspots, especially based on the resource allocation of such systems.

With the explosive growth of the number of users, the traditional centralized resource allocation algorithm is increasingly demanding for the base station. Therefore, the distributed resource allocation algorithm based on relay assistance will be a large-scale, wide-coverage high-speed mobile communication system in the future. Lieutenant will have more advantages.

Summary of the invention

The technical problem to be solved by the present invention is to provide a distributed resource allocation method applicable to a MIM0-0FDMA wireless relay system, which can effectively allocate power and subcarrier resources, and can flexibly select a replacement page (Article 26) The relay forwarding strategy and the duplex mode are suitable for systems including delay-sensitive users, and can reduce the amount of base station operations.

In order to solve the above technical problem, the present invention provides a distributed resource allocation method for a MIMO-OFDM wireless handover system, the method comprising the following steps:

(1) Initializing MIMO-0FDMA wireless relay system parameters, including parameters of base station initializing subcarrier Lagrangian multiplier, power Lagrangian multiplier, and delay sensitive user rate Lagrangian multiplier, system maximum The iteration step size of the power and sub-gradient algorithm, initializing the respective weights of each user and the minimum rate of delay-sensitive users;

(2) The relay node sequentially calculates the following magnitudes of the user terminals within the range of responsibility of each relay node according to the channel state information and the Lagrangian multiplier of the power set by the base station and the delay sensitive user rate: power allocation value, etc. Effective signal-to-noise ratio, system channel capacity, marginal benefit, subcarrier allocation value and equivalent system power allocation value and delay sensitive user throughput, and subcarrier assignment values, equivalent system power allocation values, and delay sensitive users The throughput is sent to the base station;

(3) The base station calculates the subcarrier, power, and delay sensitive user rate by using the subgradient algorithm based on the subcarrier allocation value, the equivalent system power allocation value, and the delay sensitive user throughput calculated in step (2). a Grande multiplier, and feedback the calculated new Lagrangian multiplier result to the relay node;

(4) The relay node determines whether the subcarrier allocation value and the equivalent system power allocation value reach convergence. If convergence is not reached, the system repeats steps (2) and (3), that is, the relay node according to The new Lagrangian multiplier recalculates the parameters described in step (2), and sends the new calculation result to the base station, and the base station recalculates the Lagrangian in step (3) according to the calculation result of the relay node. Multiplier; if convergence is reached, the system gets the final resource allocation result.

The invention can effectively allocate power and subcarrier resources, and can flexibly select a relay forwarding replacement page (Article 26) The strategy and duplex mode are suitable for systems with delay-sensitive users and can reduce the amount of base station operations. DRAWINGS

1 is a schematic diagram of a MIM0-0FDMA wireless relay system to which the present invention is applied.

2 is a flow chart of an implementation of the method of the present invention. detailed description

The distributed resource allocation method of the MIM0-0FDMA wireless relay system proposed by the present invention is described in detail below with reference to the accompanying drawings.

The MIM0-0FDMA wireless relay system to which the present invention is applied is shown in FIG. 1. The system has a base station, and a relay is uniformly deployed at the cell edge of the base station, and is responsible for several user terminals in respective sectors. All users access the system in the multiple access mode of 0FDMA, and all need to be relayed to be able to communicate. Some of them are delay sensitive users t _e /)J, and the rest are non-delay sensitive users.

(3⁄4 indicates a delay-sensitive user set, indicating the entire set of users). The system contains subcarriers, and each entity uses a root antenna to transmit and receive signals.

The present invention dynamically selects the following relay forwarding policies and duplex modes according to channel state information: decoding and forwarding full duplex relay (DF-FD, t=l), decoding and forwarding half duplex relay (DF-HD) , t 2), amplify and forward full-duplex relay (AF-FD, t=3), and amplify-transfer half-duplex relay (AF-HD, t=).

The method includes the following steps:

(1) MIM0-0FDMA wireless relay system initializes various parameters: The base station initializes the i-th sub-carrier, power and the Lagrangian multiplier of the A-th delay-sensitive user rate?, (' = ι, ² , ·· ), ), system maximum power, and iteration step size of the sub-gradient algorithm ('=1, ² , ³ ) _; user initializes their respective weights (U _m , delay-sensitive user initializes their respective minimum rate R eD o

Replacement page (Article 26) (2) The relay node sequentially calculates the following magnitudes of the user terminals within its responsible range according to the channel state information and the Lagrangian multiplier set by the base station.

First calculate the power allocation value:

Where, 73⁄4, „ represents the equivalent signal-to-noise ratio of the base-to-inter-relay link on the antenna 77 and the sub-carrier 7′, indicating the equivalent of the link between the relay m and the user k on the antenna n and the sub-carrier i Signal to noise ratio,

?3⁄4, „ ⁼ }3⁄4, „+?4,, „ denotes the equivalent signal-to-noise ratio of the base station on the antenna 77 and subcarrier i through the link between the relay/Z/ to the user A, indicating that the relay/^ The instantaneous loop interference power on antenna 2 and subcarrier i, the remaining parameters are as follows:

Then use the power allocation result to calculate the corresponding equivalent signal to noise ratio "3⁄4

Replacement page (Article 26)

Then calculate the system channel capacity cl: using the equivalent signal to noise ratio: _: :

∑l. g ₂ (l + ,")

[',']―

(4)

∑^log ₂ (l + 3⁄4, _n ), t = 2, 4 Next, the marginal benefit of the subcarrier allocation value is calculated from the above power allocation value and the corresponding equivalent signal to noise ratio and system channel capacitance: ^:

From the above marginal benefit 2iS, the subcarrier allocation value ΐί ¹ can be obtained.

>

[','Ί

6

0, otherwise Finally, using the power allocation value and the subcarrier allocation value ί, the equivalent system power allocation value of 3⁄4' can be obtained _:

And delay sensitive user throughput Pi ^k ,:

Replacement page (Article 26) After the relay node completes the above calculation process, the calculation result of the subcarrier allocation value ft ^] , the equivalent system power allocation value ϊ^Ι, and the delay sensitive user throughput is transmitted to the base station.

(3) The base station calculates the subcarrier, power and delay according to the subcarrier allocation value ΐ^, the equivalent system power allocation value sent by the relay node: and the calculation result of the delay sensitive user throughput^. Lagrangian multiplier for the minimum rate of sensitive users.

Ο '+ΐ) -∑∑∑∑∑3⁄4'!„

(9)

S _k (j + l) = [5 _k (j) - ξ ₃ (j) x (Pi ^k) - R ^t) )] , ^k D _m where J' denotes the number of iterations, the iteration step size (1) 2, 3) are positive numbers, if the conditions are met

∑ ² C/)<∞,∑ C/) =∞ (10) 〗 Then iterative convergence can be guaranteed. After the base station completes the calculation of the above Lagrangian multiplier, the new Lagrangian multiplier is fed back to each relay node.

(4) The relay node determines whether the subcarrier allocation value ΐ ¹ and the power allocation value reach convergence. If the convergence is not reached, steps (2) and (3) are repeated. Otherwise, the final resource allocation result is obtained, and the iterative process is exited. . The above implementation steps of the method of the present invention are all based on a rate adaptive resource allocation problem, that is, under the constraint that the total transmission power of the system is fixed, resources are allocated reasonably to maximize the system throughput rate. The method of the invention adopts a distributed resource allocation method assisted by a relay node, and the relay node first calculates the subcarrier and power allocation according to the channel state information and the Lagrangian multiplier, and then uploads the operation result to the base station; The gradient algorithm performs the calculation of the main problem according to the calculation result of the relay node, updates the Lagrangian multiplier, and delivers it to the relay. Loop iterations in this way until the resource allocation results converge.

Replacement page (Article 26) Therefore, the amount of calculation of the base station is shared by the relay node, and the balance and compromise of the system operation load are achieved. The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Replacement page (Article 26)

Claims

Claim

A distributed resource allocation method for a MIM0-0FDMA wireless relay system, the method comprising the steps of:

(1) Initializing MIM0-0FDMA wireless relay system parameters, including parameters of base station initializing subcarrier Lagrangian multiplier, power Lagrangian multiplier and delay sensitive user rate Lagrangian multiplier, system maximum The iteration step size of the total power and sub-gradient algorithm, initializing the respective weights of each user and the minimum rate of delay-sensitive users;

(2) Each relay node sequentially calculates the following magnitudes of the user terminals within the range of each relay node according to the channel state information and the Lagrangian multiplier set by the base station: power allocation value, equivalent signal to noise ratio, system channel Capacity, marginal benefit, subcarrier allocation value, equivalent system power allocation value, and throughput of delay sensitive users, and transmitting subcarrier allocation values, equivalent system power allocation values, and delay sensitive user throughput to the base station;

(3) The base station calculates the subcarrier Lagrangian multiplier and the power lager by using the sub-gradient algorithm based on the subcarrier allocation value calculated in step (2), the equivalent system power allocation value, and the delay sensitive user throughput. a Lagrangian multiplier of the Longtime multiplier and the delay sensitive user rate, and the calculated new Lagrangian multiplier result is fed back to each relay node;

(4) The relay node determines whether the subcarrier allocation value and the equivalent system power allocation value reach convergence. If convergence is not reached, the system repeats steps (2) and (3), that is, the relay node. Recalculating the parameters described in step (2) according to the new Lagrangian multiplier, and transmitting the new calculation result to the base station, and the base station recalculates the Lagrangian in step (3) according to the calculation result of the relay node. Day multiplier; if convergence is reached, the system obtains the final resource allocation result.

2. The distributed resource allocation method of the MIM0-0FDMA wireless relay system according to claim 1, wherein in step (1), the differentiation of user weights is considered, that is, different users have unequal priorities. 3. The distributed resource allocation method for a MIMO-OFDMA wireless relay system according to claim 1, wherein the relay node in step (2) can dynamically select a full-duplex FD or a half according to channel state information. Duplex HD mode, and amplify forwarding AF or decoding forwarding strategy.

4. The distributed resource allocation method for a MIMO-OFDMA wireless relay system according to claim 1, wherein the method employs a relay-assisted distributed resource allocation method.