A Hybrid ARQ Scheme Based on Polar Codes

A hybrid automatic repeat request (HARQ) scheme based on a novel class of rate-compatible polar (\mbox{RCP}) codes are proposed. The RCP codes are constructed by performing punctures and repetitions on the conventional polar codes. Simulation results over binary-input additive white Gaussian noise channels (BAWGNCs) show that, using a low-complexity successive cancellation (SC) decoder, the proposed HARQ scheme performs as well as the existing schemes based on turbo codes and low-density parity-check (LDPC) codes. The proposed transmission scheme is only about 1.0-1.5dB away from the channel capacity with the information block length of 1024 bits.Comment: Submitted to IEEE Communications Letter

Rare Decays

Studies of rare decays play an important role in the search of physics beyond the standard model. New particles may participate in the loop processes and can be probed by seeing any deviations from the standard model predictions. The very rare decay $B_s\to\mu^+\mu^-$ has been observed with the data collected by CMS and LHCb experiments. The signal seen by the ATLAS experiment is less significant but is compatible with the predictions. The measurement itself provides stringent constraints to new physics models. The first effective lifetime measurement with $B_s\to\mu^+\mu^-$ candidates has been carried out by the LHCb experiment. More data are still required to observe the $B^0\to\mu^+\mu^-$ decays. The $B\to K^*\mu^+\mu^-$ decay also proceeds through a flavour changing neutral current process, and is sensitive to the new physics. Extended measurements are carried out for $B\to K^*\mu^+\mu^-$ decays. Most of the classical physics parameters are found to be consistent with the predictions, but tensions do emerge in some of the observables. More data will help to clarify these potential deviations.Comment: 7 pages, for LHCP 2017 conferenc

Polar Coded HARQ Scheme with Chase Combining

A hybrid automatic repeat request scheme with Chase combing (HARQ-CC) of polar codes is proposed. The existing analysis tools of the underlying rate-compatible punctured polar (RCPP) codes for additive white Gaussian noise (AWGN) channels are extended to Rayleigh fading channels. Then, an approximation bound of the throughput efficiency for the polar coded HARQ-CC scheme is derived. Utilizing this bound, the parameter configurations of the proposed scheme can be optimized. Simulation results show that, the proposed HARQ-CC scheme under a low-complexity SC decoding is only about $1.0$dB away from the existing schemes with incremental redundancy (\mbox{HARQ-IR}). Compared with the polar coded \mbox{HARQ-IR} scheme, the proposed HARQ-CC scheme requires less retransmissions and has the advantage of good compatibility to other communication techniques.Comment: Accepted by WCNC 201