Throughput Maximization for Multiuser Communications with Flexible-Sector 6DMA

TL;DR

This work tackles maximizing common throughput in a multiuser downlink by introducing a flexible-sector base station with six-dimensional movable antennas (6DMA) arranged along a circular track. It develops a tractable channel and rate model, derives a closed-form per-sector power expression $\bar{p}_m(r,N_m,\bar{R})$, and solves a non-convex mixed-integer problem via a bisection over $\bar{R}$ with a two-step antenna allocation/sector-rotation scheme. It shows that equalizing the average number of users across sectors is optimal under joint optimization, and offers a low-complexity rotation design by minimizing the variance of sector user counts. Simulation results validate the theory and demonstrate significant throughput gains over conventional fixed-sector baselines, underscoring the practical potential of flexible-sector 6DMA for mmWave/terahertz networks and beyond.

Abstract

This paper presents a cost-effective and easily-deployable flexible-sector six-dimensional movable antenna (6DMA) architecture for future wireless communication networks, which enables flexible antenna configurations to match users' spatial distribution for capacity enhancement. Different from conventional sectorized base station (BS) with fixed-position antennas (FPAs), the flexible-sector 6DMA-enabled BS employs multiple directional sector antenna arrays that can flexibly move along a common circular track. By properly moving antennas across sectors and rotating all sector antenna arrays synchronously, the flexible-sector BS can adjust the coverage regions of all sectors with flexible antenna allocations over them. In particular, we consider the multiuser downlink communication employing the orthogonal multiple access (OMA) to serve users in each sector. Under this setup, we jointly optimize the sector rotation and the antenna allocation at the flexible-sector BS to maximize the average common throughput achievable for all users based on their spatial distribution. We solve this non-convex optimization problem by deriving closed-form solutions and thereby analyze the effect of users' spatial distribution on the achievable common throughput. It is shown that equal user distribution over sectors is optimal for maximizing the common throughput. Motivated by this result, we further develop a low-complexity suboptimal solution for the sector rotation that minimizes the variance of user numbers across sectors. Finally, we provide simulation results to verify our analytical results and validate the performance of our proposed solutions. It is demonstrated that the flexible-sector BS significantly improves the network throughput as compared to other benchmark schemes.

Figures (10)

• Figure 1: Illustration of the flexible-sector BS.
• Figure 2: Illustration of the sector division when $M=3$, $L=4$, $B=12$, and $r=1$.
• Figure 3: Validation of Theorem 1 with $\bar{R}=0.7~{\rm bps/Hz}$.
• Figure 4: Maximum achievable common throughput versus total transmit power for different algorithms with $M=3$.
• Figure 5: Performance comparison under a typical non-uniform user distribution scenario with $M=3$.

Theorems & Definitions (1)

• Theorem 1