Abstract
This is the first investigation focused on delivering multi-stream information to multiple multi-antenna users employing an active reconfigurable intelligent surface (aRIS)-assisted system. We conceive the joint design of the transmit precoders and of the aRIS’s power-amplified reconfigurable elements (APRES) to enhance the log-det rate objective functions for all users, which poses large-scale mixed discrete continuous problems. We develop a max-min log-det solver, which iterates quadratic-solvers of cubic complexity to maximize the nonsmooth function representing the minimum of the users’ log-det rate functions. To mitigate the computational burden associated with cubically escalating complexity in large-scale scenarios, we introduce a pair of alternative problems aimed at maximizing the smooth functions representing the sum of the users’ log-det rate function (sum log-det) and the soft minimum of the users’ log-det rate function (soft min log-det). We develop sum log-det and soft max-min solvers, leveraging closed-form expressions of scalable (linear) complexity for efficient computation. This approach ensures practicality in addressing large-scale scenarios. Furthermore, the soft min log-det enables us to enhance the log-det rates for all users and their sum, ultimately improving the quality of delivering multi-user multi-stream information.
Original language | English (US) |
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Pages (from-to) | 1 |
Number of pages | 1 |
Journal | IEEE Transactions on Communications |
DOIs | |
State | Accepted/In press - 2024 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering
Keywords
- Active reconfigurable intelligent surface (aRIS)
- Closed-form solutions
- Complexity theory
- Interference
- Metasurfaces
- Minimax techniques
- Optimization
- Vectors
- active power control
- large-scale computation
- log-det enhancement
- log-det matrix function optimization
- mixed discrete continuous optimization
- multi-user precoding