Sum Spectral Efficiency Optimization for Rate Splitting in Downlink MU-MISO: A Generalized Power Iteration Approach
- Title
- Sum Spectral Efficiency Optimization for Rate Splitting in Downlink MU-MISO: A Generalized Power Iteration Approach
- Authors
- Park, J.; Choi, J.; Poor, H.V.; Shin, W.; Lee, N.
- Date Issued
- 2021-03
- Publisher
- Institute of Electrical and Electronics Engineers Inc.
- Abstract
- In this paper, we consider a downlink multiple-input multiple-output (MIMO) system, where a rate splitting approach is applied to serve multiple users more efficiently. We formulate a sum spectral efficiency maximization problem with respect to precoders when noisy channel state information is available at the transmitter. Finding even a suboptimal solution is a very challenging task by its non-convexity and non-smoothness. To resolve this challenge, we first approximate the non-smooth minimum function by using a LogSumExp technique, and reformulate the problem as a form of the product of Rayleigh quotients, considering channel estimation error. Then we derive the first-order optimality condition. A key observation of the obtained condition is that it can be cast as a nonlinear eigenvector-dependent eigenvalue problem so that finding a leading eigenvector is equivalent to finding a local optimal solution. To this end, we propose an algorithm inspired by a power iteration method, referred to as a generalized power iteration for rate splitting. Simulation results show that the proposed method enhances the achievable performance when channel acquisition error exists. ? 2021 IEEE.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/109464
- Article Type
- Conference
- Citation
- 2021 IEEE Wireless Communications and Networking Conference Workshops, WCNCW 2021, 2021-03
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