Tractable Transmit MIMO Beampattern Design Under a Constant Modulus Constraint
Tractable Transmit MIMO Beampattern Design Under a Constant Modulus Constraint
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DOI：
10.1109/tsp.2017.2664040
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发表时间：
2017-05
影响因子：
5.4
通讯作者：
Omar Aldayel;V. Monga;M. Rangaswamy
中科院分区：
文献类型：
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作者：
Omar Aldayel;V. Monga;M. Rangaswamy
多输入多输出（MIMO）雷达系统允许每个天线元件传输不同的波形。这种波形分集可用于增强波束图设计，特别是在感兴趣的方向上有效地管理雷达辐射功率。我们解决了MIMO雷达波束方向图的设计问题，而波束方向图又由发射波形决定。虽然无约束设计很简单，但一个关键的挑战是在雷达波形上执行恒定模量约束。众所周知，在恒模约束下最小化设计波束方向图与理想波束方向图的偏差是一个困难的非凸问题。解决恒定模量的现有方法总是导致在解析可追溯性（通过松弛和近似实现）和精确实现恒定模量但计算负担沉重的实际设计之间进行艰难的权衡。本文提出了一种求解凸等式约束的二次规划序列的新方法，其中每个二次规划都有一个闭解，并且在收敛处实现常模。进一步证明了该收敛解满足上述硬非凸问题的Karush-Kuhn-Tucker最优性条件。我们在窄带和宽带设置中对所提出的连续封闭形式（SCF）算法与最先进的MIMO波束模式设计技术进行了评估，并表明SCF打破了理想性能和相关计算成本之间的权衡。
Multiple-input multiple-output (MIMO) radar systems allow each antenna element to transmit a different waveform. This waveform diversity can be exploited to enhance the beampattern design, in particular, effective management of radar radiation power in directions of interest. We address the problem of designing a beampattern for MIMO radar, which in turn is determined by the transmit waveform. While unconstrained design is straightforward, a key open challenge is enforcing the constant modulus constraint on the radar waveform. It is well known that the problem of minimizing deviation of the designed beampattern from an idealized one subject to the constant modulus constraint constitutes a hard nonconvex problem. Existing methods that address constant modulus invariably lead to a stiff tradeoff between analytical tractability (achieved by relaxations and approximations) and realistic design that exactly achieves constant modulus but is computationally burdensome. A new approach is proposed in our paper, which involves solving a sequence of convex equality constrained quadratic programs, each of which has a closed form solution and such that constant modulus is achieved at convergence. We further prove that the converged solution satisfies the Karush–Kuhn–Tucker optimality conditions of the aforementioned hard nonconvex problem. We evaluate the proposed successive closed forms (SCF) algorithm against the state-of-the art MIMO beampattern design techniques in both narrowband and wideband setups and show that the SCF breaks the tradeoff between desirable performance and the associated computation cost.