On HARQ-IR for Downlink NOMA Systems

Non-orthogonal multiple access (NOMA) can exploit the power difference between the users to achieve a higher spectral efficiency. Thus, the power allocation plays a crucial role in NOMA. In this paper, we study the power allocation for hybrid automatic repeat request (HARQ) in NOMA with two users. For the power allocation, we consider the error exponents of the outage probabilities in HARQ with incremental redundancy (IR) and derive them based on large deviations. While a closed-form expression for the error exponent (or rate function) without interference is available, there is no closed-form expression for the error exponent with interference. Thus, we focus on the derivation of a lower bound on the error exponent in this paper. Based on the error exponents, we formulate a power allocation problem for HARQ-IR in NOMA to guarantee a certain low outage probability for a given maximum number of retransmissions. From the simulation results, we can confirm that it is possible to guarantee a certain outage probability by the proposed power allocation method.

[1]  H. Vincent Poor,et al.  Design of Massive-MIMO-NOMA With Limited Feedback , 2015, IEEE Signal Processing Letters.

[2]  Jinho Choi,et al.  On Large Deviations of HARQ with Incremental Redundancy over Fading Channels , 2012, IEEE Communications Letters.

[3]  Branislav M. Popovic,et al.  Non-orthogonal multiple access for degraded broadcast channels: RA-CEMA , 2014, 2015 IEEE Wireless Communications and Networking Conference (WCNC).

[4]  Jinho Choi,et al.  Non-Orthogonal Multiple Access in Downlink Coordinated Two-Point Systems , 2014, IEEE Communications Letters.

[5]  Shin-Lin Shieh,et al.  A Simple Scheme for Realizing the Promised Gains of Downlink Nonorthogonal Multiple Access , 2016, IEEE Transactions on Communications.

[6]  Chungyong Lee,et al.  Non-orthogonal Multiple Access in a Downlink Multiuser Beamforming System , 2013, MILCOM 2013 - 2013 IEEE Military Communications Conference.

[7]  Jinho Choi,et al.  On the Power Allocation for a Practical Multiuser Superposition Scheme in NOMA Systems , 2016, IEEE Communications Letters.

[8]  Huiling Jiang,et al.  Investigation on hybrid automatic repeat request (HARQ) design for NOMA with SU-MIMO , 2015, 2015 IEEE 26th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC).

[9]  S. Wicker.  Error Control Systems for Digital Communication and Storage , 1994 .

[10]  C H Chang,et al.  EFFECTIVE BANDWIDTH IN HIGHSPEED DIGITAL NETWORKS , 1995 .

[11]  Pingzhi Fan,et al.  On the Performance of Non-Orthogonal Multiple Access in 5G Systems with Randomly Deployed Users , 2014, IEEE Signal Processing Letters.

[12]  Nihar Jindal,et al.  Performance of hybrid-ARQ in block-fading channels: A fixed outage probability analysis , 2010, IEEE Transactions on Communications.

[13]  Alan Weiss,et al.  An Introduction to Large Deviations for Communication Networks , 1995, IEEE J. Sel. Areas Commun..

[14]  Giuseppe Caire,et al.  The throughput of hybrid-ARQ protocols for the Gaussian collision channel , 2001, IEEE Trans. Inf. Theory.

[15]  Fumiyuki Adachi,et al.  The Application of MIMO to Non-Orthogonal Multiple Access , 2015, IEEE Transactions on Wireless Communications.

[16]  Shu Lin,et al.  Error control coding : fundamentals and applications , 1983 .

[17]  Muhammad Imran,et al.  Non-Orthogonal Multiple Access (NOMA) for cellular future radio access , 2017 .