UE速度和CQI时延对LTE/LTE-A系统效率的影响

摘要

Aiming at the complex time-varying characteristics of wireless channel, the adaptive modulation and coding ( AMC) technology is adopted for scheduling downlink resource to improve the reliability and performance of LTE/LTE-A system. The key of AMC technology is using real time channel quality indicator ( CQI) , the feedback from user terminal, to conduct downlink scheduling;but at present, in most of the existing LTE/LTE-A systems, the CQI delay is ignored to simplify the design of system. Thus the model of LTE/LTE -A system is established and combined with WINNER II channel model for simulated analyzing the influence of user equipment ( UE) and speed of CQI delay velouty on LTE/LTE-A system. The results show that the efficiency of LTE/LTE-A system is decreasing along with the increasing of the UE speed and CQI delay, and the impaction of UE speed and CQI delay on LTE/LTE system may be more serious under bad channel environment.%针对无线信道复杂的时变特性,采用自适应调制编码( AMC)技术进行下行资源的调度,以提高LTE/LTE-A系统的可靠性和系统性能。 AMC技术的关键是网络端使用终端反馈的实时信道质量指示( CQI)进行下行调度,但现有LTE/LTE-A系统中,为了简化系统设计,大多并未考虑CQI时延带来的影响。因此,建立LTE/LTE-A系统模型,并结合WINNER II信道模型,对不同信道环境下CQI时延和用户设备( UE)速度对LTE/LTE-A系统的影响进行仿真分析。分析结果表明,LTE/LTE-A系统的效率随着终端速度和CQI时延的增加而降低,并且在恶劣的信道环境下,终端速度和CQI时延对LTE/LTE-A系统效率的影响更严重。