In this work, we study the generalized degrees-of-freedom (GDoF) of downlink and uplink cellular networks, modeled as Gaussian interfering broadcast channels (IBC) and Gaussian interfering multiple access channels (IMAC), respectively. We focus on regimes of low inter-cell interference, where single-cell transmission with power control and treating inter-cell interference as noise (mc-TIN) is GDoF optimal. Recent works have identified two relevant regimes in this context: one in which the GDoF region achieved through mc-TIN for both the IBC and IMAC is a convex polyhedron without the need for time-sharing (mc-CTIN regime), and a smaller (sub)regime where mc-TIN is GDoF optimal for both the IBC and IMAC (mc-TIN regime). In this work, we extend the mc-TIN framework to cellular scenarios where channel state information at the transmitters (CSIT) is limited to finite precision. We show that in this case, the GDoF optimality of mc-TIN extends to the entire mc-CTIN regime, where GDoF benefits due to interference alignment (IA) are lost. Our result constitutes yet another successful application of robust outer bounds based on the aligned images (AI) approach.
翻译:在这项工作中,我们研究了下链和上链细胞网络的普遍自由度(GDoF),分别以高斯干扰广播频道(IBC)和高斯干扰多个接入频道(IMAC)为模型,我们侧重于低细胞间干扰制度,在这种制度中,带电控的单细胞传输是最佳的,并将细胞间干扰作为噪音(mc-TIN)处理。在这方面,最近的工作确定了两个相关制度:一个是GDoF区域通过Mc-TIN为IBC和IMAC提供的混合网络,不需要时间共享(mc-CTIN制度),另一个是小型(次)制度,Mc-TIN对IBC和IMAC(mc-TIN制度)来说都是最佳的。在这项工作中,我们将Mc-TIN框架扩大到蜂窝,使发射机(CIT)的频道状态信息限于有限的精确度。我们表明,在这种情况下,GDoF-F最优化的MC-TIN方法(MC-TIIN)成功地应用了我们以MC-TIN为基础的整个MC结果。