Maximum Likelihood Trellis Decoder for Golay Codes with Puncturing and Shortening for MIMO in HSPA+

HSDPA is based on shared channel transmission and its key features are shared channel and multi-code transmission, higher-order modulation, short Transmission Time Interval (TTI), fast link adaptation and scheduling along with fast hybrid Automatic Repeat request (ARQ). The HS-DPCCH channel is used in HSDPA by the UE to signal the Hybrid Automatic -Repeat-reQuest (HARQ) acknowledgements and the Channel Quality Information (CQI). The UE is using the CQI to indicate the instantaneous DL channel quality and that information is utilized in determining the UE that should be scheduled during the next TTI. This paper describes an effective working of the MIMO (Multiple Input Multiple Output) system, dependent on the accurate decoding of CQI & PCI values at the Base Transceiver station to provide flawless service to the MIMO service enabled UE. The possible values of CQI & PCI are between 0 to 1023 combinations which undergoes (20, 10) encryption at UE. The efficient decoding of the time crucial information is very much desired with least amount of complexity and highly efficient utilization of the resource available for improved downlink which provides higher data throughput with significantly reduced latency. Thus to reduce the cost per bit and enhances to mitigate the challenge to support for high-performance packet data applications for the current advent of smart phones available in the cellular communication eco-system.