针对多用户视频流在下行正交频分多址(Orthogonal Frequency Division Multiplexing,OFDM)系统中的资源调度问题,重点研究基于可伸缩视频编码(Scalable Video Coding,SVC)的视频流调度机制。SVC作为一种具有空间、时间和质量3个维度的...针对多用户视频流在下行正交频分多址(Orthogonal Frequency Division Multiplexing,OFDM)系统中的资源调度问题,重点研究基于可伸缩视频编码(Scalable Video Coding,SVC)的视频流调度机制。SVC作为一种具有空间、时间和质量3个维度的可伸缩性视频编码方案,能够为视频流在无线环境中提供灵活的传输方式,因此,研究提出一种OFDM系统中基于内容感知的SVC视频流调度算法,充分考虑不同SVC视频流分组的优先级与延迟约束,并利用OFDM技术在无线资源(时域、频域及功率)分配上的灵活性对分组进行调度。最后,研究通过仿真实验,对比了基于内容感知的SVC视频流调度算法与传统算法的性能特性,仿真结果表明所提出的调度机制相对于传统算法最高有3.2d B的平均峰值信噪比(PSNR,Peak Signal to Noise Ratio)增益。展开更多
We present a coherent and systematic review of Random Access Algorithms for packet networks, as developed over three and a half decades. We consider the appropriate user models and we classify the algorithms according...We present a coherent and systematic review of Random Access Algorithms for packet networks, as developed over three and a half decades. We consider the appropriate user models and we classify the algorithms according to the channel sensing constraints imposed. We also present a review of the analytical methodologies required for the performance analysis of these algorithms.展开更多
An improved spectrum-efficient and fair resource scheduling algorithm for multimedia broadcast multicast service(MBMS)in long term evolution(LTE)systems is proposed in this paper.By jointly considering the channel con...An improved spectrum-efficient and fair resource scheduling algorithm for multimedia broadcast multicast service(MBMS)in long term evolution(LTE)systems is proposed in this paper.By jointly considering the channel conditions of all the users,the average packet loss rate,and the fairness of users in the MBMS group,the transmission data rate of the MBMS group is first selected according to the link adaptation and the average packet loss rate of users.Then,the resource blocks are allocated to MBMS groups according to the scheduling priority.Such a resource scheduling algorithm further balances the system throughput and user fairness.Theoretical analysis and simulation results show that the proposed algorithm can achieve a good tradeoff between system throughput and user fairness in comparison with traditional scheduling algorithms.展开更多
A new Multiple Access Control (MAC) protocol-User Adaptive Scheduling Multiple Access (UASMA) protocol is proposed in this paper. It can well schedule the packet transmission according to the exact number of active Mo...A new Multiple Access Control (MAC) protocol-User Adaptive Scheduling Multiple Access (UASMA) protocol is proposed in this paper. It can well schedule the packet transmission according to the exact number of active Mobile Terminals (MTs) determined by selforganizing algorithm and adjust the number of packets sent by one node in one frame properly.UASMA protocol employs a special frame structure, which makes it possible to allocate channel resource to uplink and downlink traffic according to their respective service requirements. The proposed concept of referenced-frame-length can ensure the frame length varies in a certain range,and consequently increase the utilization efficiency of the channel greatly. Meanwhile, UASMA protocol uses an efficient collision resolution algorithm to guarantee that active MTs can access the channel rapidly. Finally, the performance of UASMA protocol is evaluated by simulation and it is also compared with carrier sense multiple access, rounding-poll and UPMA protocols. The results show that the UASMA has better performance than others.展开更多
An improved wavelet packet domain least mean square （IWPD-LMS） based adaptive muhiuser detection algorithm is proposed. The algorithm employs the wavelet packet transform to rewhiten the input data, and chooses the ...An improved wavelet packet domain least mean square （IWPD-LMS） based adaptive muhiuser detection algorithm is proposed. The algorithm employs the wavelet packet transform to rewhiten the input data, and chooses the best wavelet packet basis according to a novel convergence contribution function rather than the conventional Shannon entropy. The theoretic analyses show that the inadequacy of the eigenvalue spread of the tap-input correlation matrix is ameliorated, thus the convergence performance is improved greatly. The simulation result of convergence performance and bit error rate（BER） performance as a function of the signal power to noise power ratio（SNR） are presented finally to prove the validity of the proposed algorithm.展开更多
文摘针对多用户视频流在下行正交频分多址(Orthogonal Frequency Division Multiplexing,OFDM)系统中的资源调度问题,重点研究基于可伸缩视频编码(Scalable Video Coding,SVC)的视频流调度机制。SVC作为一种具有空间、时间和质量3个维度的可伸缩性视频编码方案,能够为视频流在无线环境中提供灵活的传输方式,因此,研究提出一种OFDM系统中基于内容感知的SVC视频流调度算法,充分考虑不同SVC视频流分组的优先级与延迟约束,并利用OFDM技术在无线资源(时域、频域及功率)分配上的灵活性对分组进行调度。最后,研究通过仿真实验,对比了基于内容感知的SVC视频流调度算法与传统算法的性能特性,仿真结果表明所提出的调度机制相对于传统算法最高有3.2d B的平均峰值信噪比(PSNR,Peak Signal to Noise Ratio)增益。
文摘We present a coherent and systematic review of Random Access Algorithms for packet networks, as developed over three and a half decades. We consider the appropriate user models and we classify the algorithms according to the channel sensing constraints imposed. We also present a review of the analytical methodologies required for the performance analysis of these algorithms.
文摘An improved spectrum-efficient and fair resource scheduling algorithm for multimedia broadcast multicast service(MBMS)in long term evolution(LTE)systems is proposed in this paper.By jointly considering the channel conditions of all the users,the average packet loss rate,and the fairness of users in the MBMS group,the transmission data rate of the MBMS group is first selected according to the link adaptation and the average packet loss rate of users.Then,the resource blocks are allocated to MBMS groups according to the scheduling priority.Such a resource scheduling algorithm further balances the system throughput and user fairness.Theoretical analysis and simulation results show that the proposed algorithm can achieve a good tradeoff between system throughput and user fairness in comparison with traditional scheduling algorithms.
基金Partly supported by the National Natural Science Foundation of China (No.60372048,No.60390540) Microsoft Research Asia, National "863" Program of China (No.2001AA123031)the Key Project of Chinese Ministry of Education (01162)Teaching Research Award Program for Outstanding Young Teachers in Higher Education Institutions of Ministry of Education, P.R.C.
文摘A new Multiple Access Control (MAC) protocol-User Adaptive Scheduling Multiple Access (UASMA) protocol is proposed in this paper. It can well schedule the packet transmission according to the exact number of active Mobile Terminals (MTs) determined by selforganizing algorithm and adjust the number of packets sent by one node in one frame properly.UASMA protocol employs a special frame structure, which makes it possible to allocate channel resource to uplink and downlink traffic according to their respective service requirements. The proposed concept of referenced-frame-length can ensure the frame length varies in a certain range,and consequently increase the utilization efficiency of the channel greatly. Meanwhile, UASMA protocol uses an efficient collision resolution algorithm to guarantee that active MTs can access the channel rapidly. Finally, the performance of UASMA protocol is evaluated by simulation and it is also compared with carrier sense multiple access, rounding-poll and UPMA protocols. The results show that the UASMA has better performance than others.
基金Sponsored by the National"863"Program Projects (2007AA012293)
文摘An improved wavelet packet domain least mean square （IWPD-LMS） based adaptive muhiuser detection algorithm is proposed. The algorithm employs the wavelet packet transform to rewhiten the input data, and chooses the best wavelet packet basis according to a novel convergence contribution function rather than the conventional Shannon entropy. The theoretic analyses show that the inadequacy of the eigenvalue spread of the tap-input correlation matrix is ameliorated, thus the convergence performance is improved greatly. The simulation result of convergence performance and bit error rate（BER） performance as a function of the signal power to noise power ratio（SNR） are presented finally to prove the validity of the proposed algorithm.
