In 5G, the Physical Downlink Control CHannel (PDCCH) carries crucial information enabling the User Equipment (UE) to connect in UL and DL. UEs are unaware of the frequency location at which PDCCH is encoded, hence they need to perform blind decoding over a limited set of possible candidates. We address the problem faced by the gNodeB of selecting PDCCH candidates for each UE to optimize data transmission. We formulate it as a Maximum Weighted Independent Set (MWIS) problem, that is known to be an NP-hard problem and cannot even be approximated. A solution method called Weight-to-Degree Ratio (WDR) Greedy emerges as a strong contender for practical implementations due to its favorable performance-to-complexity trade-off and theoretical performance guarantees.

翻译：在5G中，物理下行控制信道(PDCCH)承载着使用户设备(UE)能够在上行链路(UL)和下行链路(DL)中建立连接的关键信息。由于UE无法预知PDCCH编码所在的频率位置，因此它们需要在有限的一组候选位置上执行盲解码。针对gNodeB为每个UE选择PDCCH候选以优化数据传输的问题，我们将其建模为最大加权独立集(MWIS)问题，该问题已知为NP难问题且甚至无法近似求解。一种称为权重与度数比(WDR)贪心算法的求解方法，凭借其优越的性能-复杂度权衡和理论性能保证，成为实际实施中的有力竞争者。