LTE-U技术及其部署策略研究

本文先从LTE-U技术原理、产业发展情况以及与Wi-Fi共存的技术挑战等方面分析,然后与LWA、ANDSF等非授权频谱利用技术进行比较,再结合频谱政策等因素提出了对运营商部署LTE-U的策略建议.     

用LTE-U部署移动网络浅论

“频谱”是移动宽带网络的“生命线”,对电信运营商来说,频谱永远是最稀缺的宝贵资源。有专家预测,到2018年或2019年对于频谱的需求将远远超过频谱的供应,如何应对数据流量日益增长与频谱资源不足之间的矛盾,LTE-U技术应用而生,它是一种应用5GHZ的免授权频谱为用户提供运营商级网络服务的无线接入技术,本文结合LTE-U的技术特点和当前4G网络的建设情况浅述了LTE-U部署移动网络的前景。     

LTE-U关键技术与网络规划策略

LTE-U是一种在非授权频谱上部署LTE技术以提供电信级移动通信服务的无线接入技术.本文首先研究了LTE-U关键技术,然后从频率使用、载波聚合方案、网络部署策略、干扰规避等方面分析了LTE-U引入对网络规划的影响,针对性的提出了以提升中国移动LTE网络质量与建设效率为目标的LTE-U网络规划策略,为中国移动未来LTE-U部署提供参考.     

Performance analysis of LTE-U coexistence network with WiFi using queueing model

The unforeseen mobile data explosion as well as the scarce of spectrum resource pose a major challenge to the performance of today's cellular networks which are in urgent need of novel solutions to handle such voluminous mobile data. Long term evolution-unlicensed (LTE-U), which extends the LTE standard operating on the unlicensed band, has been proposed to improve system throughput. In LTE-U system, arriving users will contend the unlicensed spectrum resource with wireless fidelity (WiFi) users to transmit data information. Nevertheless, there is no clear consensus as to the benefits of transmission using unlicensed bands for LTE users. To this end, in this paper an analytical model is presented based on a queue system to understand the performance achieved by unlicensed based LTE system taking quality of services (QoS) and LTE-U users' behaviors into account. To obtain the stead-state solutions of the queue system, a matrix geometric method is used to solve it. Then, the average delay and utilization of unlicensed band for the LTE-U users is derived by using the queuing model. The performance of LTE-U coexistence is evaluated with WiFi using the proposed model and provide some initial insights as to the advantage of LTE-U in practice.     

LTE-U:未来移动通信系统发展的助推剂

LTE-U (LTE in unlicensed spectrum)是近来3GPP标准化组织讨论研究的用于缓解授权频段通信压力的新兴技术.首先对LTE-U技术进行概述,随后分析了LTE-U的工作频谱和设计要求,同时总结了其可能的部署场景和运行模式,然后对部署LTE-U存在的难点和现有的应用解决方案的相关研究进行了详细阐述,最后对未来的研究方向进行了展望.     

LTE-U终端发射机信号EVM测量算法研究

针对LTE-U协议的PUSCH(上行业务信道),提出了一种有效的EVM算法,可以简单、快速、精确地测量EVM。该算法中,对解调前的数据定时同步后直接进行频偏、相偏与I/Q不平衡参数的估计与补偿,以减小测量信号误差,再经过解调与再调制准确恢复参考信号,并最终实现EVM的测量。仿真和实验结果表明,该算法EVM的仿真结果与理论值接近,可满足测试的精度要求,可以为LTE-U射频一致性测试系统提供理论基础。     

A Survey on Technologies and Challenges of LTE-U

The rapid growth of mobile data traffic has caused great pressure on the limited spectrum resources, and there must be some better methods to deal with this problem. The innovative technology of Long-Term Evolution (LTE) using the unlicensed spectrum, known as LTE-Unlicensed (LTE-U), has been proposed to effectively alleviate the shortage of authorized band resources. LTE-U has explored a lot of potential capacity in mobile communication systems with limited authorized spectrum resources, and improved the spectrum utilization of unauthorized frequency bands. However, LTE-U is still facing challenges in its application. In this paper, we summarize the key features of LTE-U and the coexistence of LTE-U with Wi-Fi in the unlicensed Spectrum. We analyze the key technologies (including carrier aggregation, HARQ, interference cancelation, and centralized scheduling), the operating modes and deployment scenarios (including carrier aggregation LTE-U, duty cycle LTE-U, and standalone LTE-U), and the advantages (including anchored LTE-U and Standalone LTE-U scenarios), as well as main technical challenges. We then address the different management mechanisms of LTE-U and Wi-Fi (including the differences between the MAC layer and physical layer), the types of coexistence technology classification (including channel separation and channel sharing technologies), and directions for future work. We hope that this comprehensive survey spurs further research in this promising area.