Sum-Rate Maximization of Uplink Rate Splitting Multiple Access (RSMA) Communication

Abstract

In this paper, the problem of maximizing the wireless users' sum-rate for uplink rate splitting multiple access (RSMA) communications is studied. In the considered model, each user transmits a superposition of two messages to a base station (BS) with separate transmit power and the BS uses a successive decoding technique to decode the received messages. To maximize each user's transmission rate, the users must adjust their transmit power and the BS must determine the decoding order of the messages transmitted from the users to the BS. This problem is formulated as a sum-rate maximization problem with proportional rate constraints by adjusting the users' transmit power and the BS's decoding order. However, since the decoding order variable in the optimization problem is discrete, the original maximization problem with transmit power and decoding order variables can be transformed into a problem with only the rate splitting variable. Then, the optimal rate splitting of each user is determined.Given the optimal rate splitting of each user and a decoding order, the optimal transmit power of each user is calculated. Next, the optimal decoding order is determined by an exhaustive search method. To further reduce the complexity of the optimization algorithm used for sum-rate maximization in RSMA, a user pairing based algorithm is introduced, which enables two users to use RSMA in each pair and also enables the users in different pairs to be allocated with orthogonal frequency. For comparisons, the optimal sum-rate maximizing solutions with proportional rate constraints are obtained in closed A preliminary version of this work was submitted to IEEE Globecom 2019 [1]. . 2 form for non-orthogonal multiple access (NOMA), frequency division multiple access (FDMA), and time division multiple access (TDMA). Simulation results show that RSMA can achieve up to 10.0%, 22.2%, and 83.7% gains in terms of sum-rate compared to NOMA, FDMA, and TDMA. Index TermsRate splitting multiple access (RSMA), decoding order, power management, resource allocation.

Rate-Splitting Multiple Access for URLLC Uplink in Physical Layer Network Slicing With eMBB

“…While the decoding orders (ii) and (iii) achieve the same results of U-NOMA with U U,1 → U U,2 and U U,2 → U U,1 , respectively [48], is has been shown that (i) represents the optimal decoding order of RSMA [49]. Thus, in the SIC process, the receiver first attempts to decode a (virtual) user while regarding all the remaining messages as noise.…”

“…Recently, several works studied different RSMA implementations in downlink wireless networks [20]- [24], showing that RSMA can improve downlink rate and quality of service, achieving better performance than both NOMA and SDMA. For uplink RSMA systems, authors from [25], [26] study the problem of maximizing the sum-rate under proportional rate constraints for all users, by setting users transmission power and optimizing the decoding order at the BS through exhaustive search. As a result, they show that RSMA achieves better performance than NOMA and OMA techniques, such as frequency division multiple access (FDMA) and time division multiple access (TDMA).…”

Multiple Access in Aerial Networks: From Orthogonal and Non-Orthogonal to Rate-Splitting

“…In [109], RSMA-based C-RAN is realized using several gBSs and aBSs, whereas, the authors of [110] reported the energy efficiency of an RSMA-based gBS towards aerial users. Finally, [111], [112] investigated the downlink and uplink SISO RSMA parameters optimization, supporting that their results would serve as a benchmark for the MIMO system. A summary of RSMA related work is presented in Table V. RSMA is more robust and achieves significantly higher throughput than SDMA and NOMA with and without QoS constraints in the considered imperfect CSIT settings.…”

“…For multiple users, RSMA realizes up to 15.6% and 21.5% sum rate gains compared to NOMA and OFDMA, respectively, given one SIC layer only for RSMA and NOMA. [112] Multi-user SISO uplink. Max.…”

Efficient Resource Management for Sum Capacity Maximization in 5G NOMA Systems

“…Their simulation results shown better performance compared to the baseline schemes. Moreover, the authors of References [28,29] have also provided the rate and power allocation optimization for downlink and uplink transmission in rate splitting multiple access (RSMA) based wireless networks.…”