On the Selection of Guard Period and Cyclic Prefix for Beyond 4G TDD Radio Access Network

In parallel with ongoing standardization of third generation partnership project (3GPP) Long Term Evolution - Advanced (LTE-A), also referred as 4G, the discussion on next generation beyond 4G (B4G) radio access technologies is already active. Purpose of B4G system, expected to be available in 2020, is to cope with the exponential increase of mobile data traffic. In this paper we analyze the feasibility of LTE-A and wireless local area network (WLAN) physical frames against B4G requirements and discuss how the B4G environment, radio channel properties and evolved component technology affect the design of the physical layer frame. We analyze the B4G physical subframe numerology including aspects such as time division duplex (TDD) switching time and cyclic prefix (CP) duration. The proposed numerology allows to design a B4G-optimized TDD physical subframe structure which further enables reaching the very tight physical layer round trip time (RTT) requirements.