Next Generation Multiple Access: Performance Gains From Uplink MIMO-NOMA

Abstract

The use of multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) based communication protocols is proposed and investigated for the uplink of wireless networks with buffered data-sources, which is the basis of the introduced medium access control (MAC)-layer protocol. To this end, the long-term average throughput is maximized by optimizing the set of users that transmit information at each time slot and their transmit power, the number of packets that are admitted in each user's queue, and the transmission rates, assuming that the instantaneous channel state information is not available at the transmitters. Also, considering a receiver with multiple antennas, two detection techniques are used to mitigate the interference when two users are chosen to simultaneously transmit information in the same resource block, namely successive interference cancellation (SIC) and joint decoding (JD). More specifically, the outage probability for both considered techniques is derived in closed-from, which is a prerequisite for the derivation and the optimization of the throughput. The formulated multi-dimensional long-term stochastic optimization problem is solved by using the Lyapunov framework. Finally, simulation results verify the gains by using MIMO-NOMA as the basis of the next generation multiple access and illustrate the superiority of JD compared to SIC with respect to the number of the receiver's antennas.

On the Coexistence of Heterogeneous Services in 6G Networks: An Imperfection-Aware RSMA Framework

“…According to the pSIC case, having successfully decoded x u1 and exploiting the channel estimation ĥu , the BS is capable of generating the term √ a 1 P ĥu x u1 and perfectly removing it from the received y II B presented in (5). Conversely, assuming ipSIC, the aforementioned term is not completely removed from (5) and, thus, the decoding of x f is attempted in the presence of residual interference due to ipSIC.…”

“…The fulfillment of these requirements is essential for meeting the needs of 6G types of services, including further-enhanced mobile broadband (feMBB), extremely reliable and low-latency communication (eRLLC), ultra massive machine-type communication (umMTC), as well as their combinations [3]. To effectively meet these stringent requirements, one of the fundamental necessities is the development of sophisticated multiple access schemes suitable for the next generation of wireless networks, referred to as next-generation multiple access [4], [5].…”

Breaking Orthogonality in Uplink With Randomly Deployed Sources

“…Furthermore, determining the outage probability for uplink NOMA is crucial as it lays the foundation for the design and optimization of practical medium access control (MAC) schemes. In this context, the outage probability for uplink NOMA with both single-antenna and multi-antenna BSs was established in [20] and [21], respectively, assuming stationary user positions.…”