Overview of LTE-Advanced and Standardization Trends

Release 8 (hereinafter referred to as “LTE Rel. 8”) specifications [1][2] which completed standardization by the 3GPP in the spring of 2009. LTE Rel. 8 adopts various high-level radio interface technologies such as orthogonal multi-access, frequency-domain scheduling and Multiple Input Multiple Output (MIMO) *2 , and provides even higher system capacity and cell edge user throughput than High Speed Packet Access (HSPA) *3 . It also significantly reduces transmission and connection set up delays, making major improvements on system performance[3]. NTT DOCOMO is playing a central role in advancing the standardization of LTE in the 3GPP, from proposing the basic concepts to completing the specifications. NTT DOCOMO is also supporting the standardization of LTE Rel. 9, which will further increase the sophistication of LTE, enabling the economical introduction of many different services, and meeting the demands of LTE users in the future. LTE Rel. 9, which was completed in spring, 2010, provides various new functions including Closed Subscriber Group (CSG) functions, extensions to network self-optimization, location information services and Multimedia Broadcast and Multicast Services (MBMS) [4]. NTT DOCOMO is also promoting the standardization of LTE-Advanced (LTE Rel. 10 and beyond), which will further increase the system performance of radio access networks. This is in consideration of the need to respond quickly to the demands of traffic which is expected to increase dramatically as