Analysis of LTE Physical Hybrid ARQ Control Channel

A Physical Hybrid ARQ Indicator Channel (PHICH) is a very important element of the Long Term Evolution (LTE), Release 8 communication system. Via the PHICH, a Hybrid ARQ Indicator (HI) acknowledge message is transmitted. The HI informs the result if the previous data transfer in uplink direction. Imperfect protection of PHICH transfer can cause superfluous repetitions of incorrect confirmed data and uplink overhead grows. In the paper, the PHICH signal processing and performance results of a single HI message in AWGN and fading channel models are presented depending on the representative antenna modes. The performance results for a number of HI messages greater than one within a single PHICH group, have not been found.