Integrated data and energy transfer (IDET) is a promising technique for supporting sustainable low-power wireless networks. To improve both communication reliability and energy transfer efficiency, this paper investigates a fluid index modulation (FIM) assisted IDET system, where the base station employs a two-dimensional fluid antenna system (FAS) and the receiver adopts a power-splitting architecture. In FIM, the information bits are delivered not only from the modulation symbols, but also the index of antenna position. Under finite-alphabet signaling, the average harvested power, bit error rate (BER), and achievable data rate are derived in closed form. A joint optimization problem is formulated to maximize the average harvested power subject to BER and achievable rate constraints by jointly optimizing the port selection, precoding vector, and power splitting ratio. An alternating optimization framework is developed, where the precoding vector and port selection are obtained via a Riemannian augmented Lagrangian method (RALM) and block coordinate descent (BCD) algorithm, respectively. Simulation results demonstrate that the proposed scheme achieves a superior rate-energy trade-off over benchmark schemes, while the proposed algorithm attains near-optimal performance with significantly lower complexity than exhaustive search.

翻译：集成数据与能量传输(IDET)是支持可持续低功耗无线网络的一项有前景的技术。为提升通信可靠性与能量传输效率，本文研究了基于流体索引调制(FIM)的IDET系统，其中基站采用二维流体天线系统(FAS)，接收端采用功率分配架构。在FIM中，信息比特不仅通过调制符号传递，还通过天线位置索引传递。针对有限字母表信号，以闭式推导出平均采集功率、误码率(BER)与可达数据速率。构建了联合优化问题，在BER与可达速率约束下通过联合优化端口选择、预编码向量及功率分配比最大化平均采集功率。提出交替优化框架，其中预编码向量与端口选择分别通过黎曼增广拉格朗日法(RALM)与块坐标下降(BCD)算法求解。仿真结果表明，所提方案相较于基准方案实现了更优的速率-能量权衡，且所提算法以显著低于穷举搜索的复杂度获得近优性能。