Butterfly-Flow-Graph Based MAP Decoding Algorithm for Channel Quality Information in 3GPP-LTE
Channel quality information (CQI) is an essential element of uplink control signaling in Long Term Evolution (LTE) system. According to 3GPP standard, a linear block code based on Reed-Muller (RM) code has been employed for the CQI transmission for error control. In this paper, a low complexity maximum a posteriori probability (MAP) decoding algorithm for CQI decoding is described, which is performed by re-ordering the likelihood values of the received signal and all mapped codewords, and then calculating the probability of 0 and 1 of every transmitted information bit based on a butterfly-flow-graph (BFG). Compared to the standard MAP decoding algorithm, the proposed algorithm can reduce the addition calculation by 35.71% to 72.82% when the number of CQI bit is changing from 4 to 11, and the bit error rate (BER) performance is without degradation.
Keywords3GPP-LTE CQI MAP decoding
- 1.Ramli, H.A.M., Sukor, M.A.: Performance analysis on automated and average channel quality information (CQI) reporting algorithm in LTE-A. In: 2016 International Conference on Computer and Communication Engineering (2016)Google Scholar
- 2.3GPP: TS36.212, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding (Release 12) (2015)Google Scholar
- 4.Li, M., Han, D., Ma, S.: Decoding algorithm with fast Hadamard transform for channel quality indication (CQI) in 3GPP-LTE, In: 2010 International Conference on Computer Application and System Modeling (2010)Google Scholar