The transmission antennas of cooperative systems are spatially distributed on multiple nodes, so the received signal can be asynchronous due to propagation delays. A receiving scheme for cooperative relay networks is ...The transmission antennas of cooperative systems are spatially distributed on multiple nodes, so the received signal can be asynchronous due to propagation delays. A receiving scheme for cooperative relay networks is proposed, multiple asynchronous signals are reconstructed at the receiver by forward and backward interference cancellation, which can obtain gains of cooperative transmission diversity with obvious delay and with no requiring timing synchronization or orthogonal channelization between relays. Analysis and simulation show that the bit error rate（BER） of the proposed scheme is similar to Alamouti code, and the scheme has the diversity order of orthogonal transmission scheme accompanied by minimal BER losses. It is demonstrated that the performance can be further improved by adding an error correcting code（ECC）.展开更多
The multi-cell uplink power allocation problem for orthogonal frequency division multiplexing access （OFDMA） cellular networks is investigated with the uplink transmission power allocation on each co-frequency subch...The multi-cell uplink power allocation problem for orthogonal frequency division multiplexing access （OFDMA） cellular networks is investigated with the uplink transmission power allocation on each co-frequency subchannel being defined as a multi-cell non-cooperative power allocation game （MNPG）.The principle of the design of the utility function is given and a novel utility function is proposed for MNPG.By using this utility function,the minimum signal to interference plus noise ratio （SINR） requirement of a user can be guaranteed.It can be shown that MNPG will converge to the Nash equilibrium and that this Nash equilibrium is unique.In considering the simulation results,the effect of the algorithm parameters on the system performance is discussed,and the convergence of the MNPG is verified.The performance of MNPG is compared with that of traditional power allocation schemes,the simulation results showing that the proposed algorithm increases the cell-edge user throughput greatly with only a small decrease in cell total throughput; this gives a good tradeoff between the throughput of cell-edge users and the system spectrum efficiency.展开更多
In wireless cellular networks, the interference alignment （IA） is a promising technique for interference management. A new IA scheme for downlink cellular network with multi-cell and multi-user was proposed, in the ...In wireless cellular networks, the interference alignment （IA） is a promising technique for interference management. A new IA scheme for downlink cellular network with multi-cell and multi-user was proposed, in the proposed scheme, the interference in the networks is divided into inter-cell interference （ICI） among cells and inter-user interference （IUI） in each cell. The ICI is aligned onto a multi-dimensional subspace by multiplying the ICI alignment precoding matrix which is designed by the singular value decomposition （SVD） scheme at the base station （BS） side. The aligned ICI is eliminated by timing the interference suppression matrix which is designed by zero-forcing （ZF） scheme at the user equipment （UE） side. Meanwhile, the IUI is aligned by multiplying the IUI alignment precoding matrix which is designed based on Nash bargaining solution （NBS） in game theory. The NBS is solved by the particle swarm optimization （PSO） method. Simulations show that, compared with the traditional ZF IA scheme, the proposed scheme can obtain higher data rate and guarantee the data rate fairness of UEs with little additional complexity.展开更多
By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile no...By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node （MN） needs to orderly accomplish two binding updates with the MAP and home agent （HA） when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given.展开更多
To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer（P2P） streaming service, an evolved layered P2P （E-LP2P） data schedulin...To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer（P2P） streaming service, an evolved layered P2P （E-LP2P） data scheduling scheme in the process of service delivery is introduced in this paper. The data in base layer is scheduled according to its importance in streaming play to guarantee the basic play of streaming. The data in enhancement layer is scheduled according to the characters of streaming data, including its position and amount in server peer set in a multiple tied way towards the data in enhancement layer. To cope with the layer jitter caused by the fluctuation of bandwidth, jitter prevent mechanism is used to adjust the highest layer dynamically during the process of data scheduling. Simulation results show that the E-LP2P can provide good quality of service（QoS） performance in terms of throughput, layer delivery ratio, server load and useless packet ratio.展开更多
基金supported by the National Science&Technology Major Projects(2012ZX03001031-004)the Fundamental Research Funds for the Central Universities(2012RC0105)
文摘The transmission antennas of cooperative systems are spatially distributed on multiple nodes, so the received signal can be asynchronous due to propagation delays. A receiving scheme for cooperative relay networks is proposed, multiple asynchronous signals are reconstructed at the receiver by forward and backward interference cancellation, which can obtain gains of cooperative transmission diversity with obvious delay and with no requiring timing synchronization or orthogonal channelization between relays. Analysis and simulation show that the bit error rate（BER） of the proposed scheme is similar to Alamouti code, and the scheme has the diversity order of orthogonal transmission scheme accompanied by minimal BER losses. It is demonstrated that the performance can be further improved by adding an error correcting code（ECC）.
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China (60772110)
文摘The multi-cell uplink power allocation problem for orthogonal frequency division multiplexing access （OFDMA） cellular networks is investigated with the uplink transmission power allocation on each co-frequency subchannel being defined as a multi-cell non-cooperative power allocation game （MNPG）.The principle of the design of the utility function is given and a novel utility function is proposed for MNPG.By using this utility function,the minimum signal to interference plus noise ratio （SINR） requirement of a user can be guaranteed.It can be shown that MNPG will converge to the Nash equilibrium and that this Nash equilibrium is unique.In considering the simulation results,the effect of the algorithm parameters on the system performance is discussed,and the convergence of the MNPG is verified.The performance of MNPG is compared with that of traditional power allocation schemes,the simulation results showing that the proposed algorithm increases the cell-edge user throughput greatly with only a small decrease in cell total throughput; this gives a good tradeoff between the throughput of cell-edge users and the system spectrum efficiency.
基金supported by the National Key Technology R&D Program of China (2012ZX03001031-004)State Key Laboratory of Wireless Mobile Communications (China Academy of Telecommunication Technology)
文摘In wireless cellular networks, the interference alignment （IA） is a promising technique for interference management. A new IA scheme for downlink cellular network with multi-cell and multi-user was proposed, in the proposed scheme, the interference in the networks is divided into inter-cell interference （ICI） among cells and inter-user interference （IUI） in each cell. The ICI is aligned onto a multi-dimensional subspace by multiplying the ICI alignment precoding matrix which is designed by the singular value decomposition （SVD） scheme at the base station （BS） side. The aligned ICI is eliminated by timing the interference suppression matrix which is designed by zero-forcing （ZF） scheme at the user equipment （UE） side. Meanwhile, the IUI is aligned by multiplying the IUI alignment precoding matrix which is designed based on Nash bargaining solution （NBS） in game theory. The NBS is solved by the particle swarm optimization （PSO） method. Simulations show that, compared with the traditional ZF IA scheme, the proposed scheme can obtain higher data rate and guarantee the data rate fairness of UEs with little additional complexity.
基金supported by the Natural Science Foundation of Jiangsu Province (BK2009469)the Fundamental Research Funds for the Central Universities (BUPT2009RC0120)the National Natural Science Foundation of China (60772110)
文摘By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node （MN） needs to orderly accomplish two binding updates with the MAP and home agent （HA） when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given.
基金supported by the National Natural Science Foundation of China (60902047)the Fundamental Research Funds for the Central Universities (BUPT 2009RC0120)
文摘To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer（P2P） streaming service, an evolved layered P2P （E-LP2P） data scheduling scheme in the process of service delivery is introduced in this paper. The data in base layer is scheduled according to its importance in streaming play to guarantee the basic play of streaming. The data in enhancement layer is scheduled according to the characters of streaming data, including its position and amount in server peer set in a multiple tied way towards the data in enhancement layer. To cope with the layer jitter caused by the fluctuation of bandwidth, jitter prevent mechanism is used to adjust the highest layer dynamically during the process of data scheduling. Simulation results show that the E-LP2P can provide good quality of service（QoS） performance in terms of throughput, layer delivery ratio, server load and useless packet ratio.
