Successive interference cancelation‐inspired channel estimation for downlink non‐orthogonal multiple access

Abstract

This paper proposes a channel estimation (CE) scheme composed of two successive interference cancelation-inspired approaches for a two-user power domain downlink non-orthogonal multiple access system. One approach is intended for the weaker user, and the other approach is intended for the stronger user. Both CE approaches employ a constant step-size least mean squares (CSS-LMS) algorithm, using partial pilots to estimate a Rayleigh flat fading channel with a Jake's Doppler spectrum. Closed-form analytical expressions for the CE error variance are presented for each approach and the mean square error (MSE) is used as the performance metric. Through simulation, the CE performance of the stronger user and the weaker user is assessed for different probabilities of error in detection of the unknown pilot. A reasonable probability of error in detection is then selected and employed in evaluating the CE performance of both schemes against their theoretical analyses. Overall, the theoretical analysis matches the simulation results.

Handoff optimization for joint base station association and power control in uplink non‐orthogonal multiple access small cell networks

“…is the optimal objective value of problem (22) in time frame t for a given r(t) , and r(t) is the vector of ( rX b kn ) (t) 's. Due to the convex nature of P5, the subproblem (22) and master problem (23) are both convex problems. Subproblem ( 22) is a linear program and can be solved with simplex-based methods or interior point methods.…”

“…NOMA with SIC is an important research topic on improving the spectrum and energy efficiencies. [17][18][19][20][21][22][23] For example, the bit error rate (BER) performance was improved and the inter-user interference was mitigated using the user grouping scheme in the work of Kim et al 17 for a NOMA system in a multi-user case. Zhang et al 18 studied the spectral and energy efficiencies tradeoff in a downlink NOMA-based heterogeneous networks (HetNets).…”

“…NOMA with SIC is an important research topic on improving the spectrum and energy efficiencies 17‐23 . For example, the bit error rate (BER) performance was improved and the inter‐user interference was mitigated using the user grouping scheme in the work of Kim et al 17 for a NOMA system in a multi‐user case.…”

“…Ni et al 22 proposed a users' scheduling scheme and a distributed power control algorithm in NOMA heterogeneous network to improve spectral efficiency. Sekokotoana et al 23 presented a channel estimation (CE) scheme consisting of two SIC‐inspired approaches for a two‐user power domain NOMA system. This work aimed to maximize the sum rate of users while considering the fairness issue.…”