Simultaneous Transmitting and Reflecting (STAR)-RIS for Harmonious Millimeter Wave Spectrum Sharing
Simultaneous Transmitting and Reflecting (STAR)-RIS for Harmonious Millimeter Wave Spectrum Sharing
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DOI：
10.1109/wcnc55385.2023.10118966
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发表时间：
2023-01
期刊：
影响因子：
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通讯作者：
Omar Hashash;W. Saad;M. Imani;David R. Smith
中科院分区：
文献类型：
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作者：
Omar Hashash;W. Saad;M. Imani;David R. Smith
用于5G通信的毫米波（mmWave）频谱带的开放激发了对这些高频下的新型频谱共享解决方案的需求。事实上，最近出现了可重新配置的智能表面（RIS），以实现频谱共享，同时提高现任者的服务质量（QoS）。尽管如此，由于毫米波波段的不利传播特性，毫米波波段的共存仍然具有持续的挑战性。因此，发起毫米波频谱共享需要RIS进一步帮助改善毫米波频带上的QoS，而不危及频谱共享需求。本文提出了一种新的同时发射和反射RIS（STAR-RIS）辅助解决方案，以实现毫米波频谱共享。特别是，STAR-MS的发射和反射能力被用来分别解决毫米波频谱共享和QoS要求。在主网络（例如雷达发射-接收对）和辅网络之间的STAR-RIS使能的频谱共享问题被公式化为优化问题，其目标是最大化辅多输入单输出（MISO）网络上的下行链路和速率，同时限制主网络上的干扰。此外，STAR-MS的响应系数和波束形成矩阵在次级网络中的联合优化。为了解决这个非凸问题，交替迭代算法，其中的STAR-RIS响应系数和波束形成矩阵使用逐次凸逼近方法获得。仿真结果表明，所提出的解决方案优于传统的RIS计划毫米波频谱共享，实现了14.57%的频谱效率增益。
The opening of the millimeter wave (mmWave) spectrum bands for 5G communications has motivated the need for novel spectrum sharing solutions at these high frequencies. In fact, reconfigurable intelligent surfaces (RISs) have recently emerged to enable spectrum sharing while enhancing the incumbents’ quality-of-service (QoS). Nonetheless, co-existence over mm Wave bands remains persistently challenging due to their unfavorable propagation characteristics. Hence, initiating mmWave spectrum sharing requires the RIS to further assist in improving the QoS over mmWave bands without jeopardizing spectrum sharing demands. In this paper, a novel simultaneous transmitting and reflecting RIS (STAR-RIS)-aided solution to enable mmWave spectrum sharing is proposed. In particular, the transmitting and reflecting abilities of the STAR-MS are leveraged to tackle the mmWave spectrum sharing and QoS requirements separately. The STAR-RIS-enabled spectrum sharing problem between a primary network (e.g. a radar transmit-receive pair) and a secondary network is formulated as an optimization problem whose goal is to maximize the downlink sum-rate over a secondary multiple-input-single-output (MISO) network, while limiting interference over a primary network. Moreover, the STAR-MS response coefficients and beamforming matrix in the secondary network are jointly optimized. To solve this non-convex problem, an alternating iterative algorithm is employed, where the STAR-RIS response coefficients and beamforming matrix are obtained using the successive convex approximation method. Simulation results show that the proposed solution outperforms conventional RIS schemes for mmWave spectrum sharing by achieving a 14.57% spectral efficiency gain.