Frame length optimization for multi-antenna downlink systems based on delay-bound violation probability constraints

A flame length optimization scheme is proposed for multi-antenna downlink systems to guarantee diverse delay- bound violation probability constraints. Due to the difficulties of extracting the quality of service （QoS） metrics from the conventional physical-layer channel models, the link-layer models named effective bandwidth and effective capacity are applied to statistically characterize the source traffic patterns and the queuing service dynamics. With these link-layer models, the source traffic process and the channel service process are mapped to certain QoS parameters. The packet delay-bound violation probability constraints are converted into minimum data rate constraints and the optimization problem is thus formulated into simultaneous inequalities. With the assumption of ergodic block-fading channels, the optimal frame lengths of single-user and multiuser systems are calculated respectively by numerical iterative methods. Theoretical analyses and simulation results show that the given delay-bound violation probability constraints are well satisfied with the optimal frame length.

考虑数据传输成功率的光网络最优通信路径选择

为全面评估通信路径性能,提升数据传输的可靠性与稳定性,研究考虑数据传输成功率的光网络最优通信路径选择方法。以最大化数据传输成功概率与最小化数据传输超时概率为目标函数,建立光网络最优通信路径选择模型;蚁群算法依据选择概率,生成初始光网络最优通信路径选择模型的可行解集合;利用遗传算法对可行解集合进行选择、交叉与变异处理,得到新的最优通信路径选择模型可行解集合;通过数据传输成功概率与超时概率,设计遗传算法的适应度,以最优适应度对应的可行解集合为最终可行解集合;利用蚁群算法在最终可行解集合内,选择最大数据传输成功概率,以及最小超时概率对应的最优通信路径。实验证明:该方法可有效生成初始光网络最优通信路径模型的可行解集合,并完成最优通信路径选择,提升数据传输成功概率,降低数据传输超时概率;应用该方法后,光网络的网络状态指示值较高,即光网络的整体性能较优。