捕获效应对LTE授权辅助接入网络的影响

Impact of Capture Effect on LTE-Licensed Assisted Access Networks

LTE授权辅助接入(LAA)和WiFi网络的共存性能已经被广泛研究。然而,这些工作忽略了捕获效应,即当两个以上的信号在相同信道上同时传输时,最强的信号仍然可能成功接收。这种现象在共存场景中可能比在WiFi网络中更频繁地发生。基于此,该文深入研究了LAA和WiFi网络在捕获效应下的共存性能。具体地,在共存场景中首先提出了两个以上信号的捕获模型,并推导出了捕获概率;然后,将LAA接入方案建模为具有捕获效应的新的2维离散马尔可夫模型,其中退避计数器的减少不仅取决于空闲的时隙,还取决于捕获效应发生的时隙;最后推导出共存性能的表达式。大量的仿真和数值结果验证了所提出的马尔可夫链和捕获模型的有效性。而且,仿真结果也证明了考虑捕获效应的必要性。

The coexistence performance of LTE-licensed Assisted Access(LAA)and WiFi networks has been extensively investigated.However,these works ignore capture effect,which is the phenomenon that the strongest signal may still be successfully received when more than two signals are transmitted simultaneously on the same channel,and which may occur more frequently in the coexistence scenario than in the pure WiFi network.Therefore,in this paper,the coexistence performance of LAA and WiFi networks with the capture effect is deeply investigated.More specifically,a capture model for more than two signals is firstly proposed in the coexistence scenario,and the capture probability is derived.Then the LAA access scheme is modeled as a new two-dimensional discrete Markov model with the capture effect,where the decrease of the backoff counter depends not only on the idle time slots but also on the time slots in which capture effect occurs.Finally,the expressions for coexistence performance are derived.A large number of simulation and numerical results verify the validity of the proposed Markov chain and capture model.The results prove the necessity of considering the capture effect in coexistence performance evaluation.