This study proposes a new multiple access con-trol protocol named distributed synchronous reservation mul-tiple access control protocol,in which the hidden and exposed terminal problems are solved,and the quality of s...This study proposes a new multiple access con-trol protocol named distributed synchronous reservation mul-tiple access control protocol,in which the hidden and exposed terminal problems are solved,and the quality of service(QoS)requirements for real-time traffic are guaranteed.The protocol is founded on time division multiplex address and a different type of traffic is assigned to different priority,according to which a node should compete for and reserve the free slots in a different method.Moreover,there is a reservation acknowledgement process before data transmit in each reserved slot,so that the intruded terminal problem is solved.The throughput and average packets drop probability of this protocol are analyzed and simulated in a fully connected network,the results of which indicate that this protocol is efficient enough to support the real-time traffic,and it is more suitable to MANETs.展开更多
Considering that weak channel collision detection ability, long propagation delay and heavy load in LEO satellite communications, a valid adaptive APRMA MAC protocol was proposed. Different access probability function...Considering that weak channel collision detection ability, long propagation delay and heavy load in LEO satellite communications, a valid adaptive APRMA MAC protocol was proposed. Different access probability functions for different services were obtained and appropriate access probabilities for voice and data users were updated slot by slot based on the estimation of the voice traffic and the channel status. In the proposed MAC protocol limited wireless resource is allocated reasonably by multiple users and high capacity was achieved. Three performance parameters: voice packet loss probability, average delay of data packets and throughput of data packets were considered in simulation. Finally simulation results demonstrated that the performance of system was improved by the APRMA compared with the conventional PRMA, with an acceptable trade-off between QoS of voice and delay of data.展开更多
综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方...综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方法。该方法利用部分子载波降低系统PAPR,同时对系统进行自适应子载波分配达到联合优化。仿真结果表明,该方法中系统的PAPR抑制效果和吞吐量参数能够同时得到优化。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.60372048,60496316)the Hi-Tech Research and Development Program of China(No.2005AA123910).
文摘This study proposes a new multiple access con-trol protocol named distributed synchronous reservation mul-tiple access control protocol,in which the hidden and exposed terminal problems are solved,and the quality of service(QoS)requirements for real-time traffic are guaranteed.The protocol is founded on time division multiplex address and a different type of traffic is assigned to different priority,according to which a node should compete for and reserve the free slots in a different method.Moreover,there is a reservation acknowledgement process before data transmit in each reserved slot,so that the intruded terminal problem is solved.The throughput and average packets drop probability of this protocol are analyzed and simulated in a fully connected network,the results of which indicate that this protocol is efficient enough to support the real-time traffic,and it is more suitable to MANETs.
文摘Considering that weak channel collision detection ability, long propagation delay and heavy load in LEO satellite communications, a valid adaptive APRMA MAC protocol was proposed. Different access probability functions for different services were obtained and appropriate access probabilities for voice and data users were updated slot by slot based on the estimation of the voice traffic and the channel status. In the proposed MAC protocol limited wireless resource is allocated reasonably by multiple users and high capacity was achieved. Three performance parameters: voice packet loss probability, average delay of data packets and throughput of data packets were considered in simulation. Finally simulation results demonstrated that the performance of system was improved by the APRMA compared with the conventional PRMA, with an acceptable trade-off between QoS of voice and delay of data.
文摘综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方法。该方法利用部分子载波降低系统PAPR,同时对系统进行自适应子载波分配达到联合优化。仿真结果表明,该方法中系统的PAPR抑制效果和吞吐量参数能够同时得到优化。
