Cache-Aided Interference Management in Partially Connected Wireless Networks

Cache-aided communication is emerging as a new topic in wireless networks. Previous works have shown that caching in interference networks can change the interference topology by changing the information flow and hence facilitate advanced interference management. This paper studies the gain of caching in partially connected interference networks where each receiver can only communicate with a subset of transmitters. The performance is characterized by an information-theoretic metric, normalized delivery time (NDT). We obtain an order-optimal NDT for the (K + L - 1) x K partially connected linear interference network with any number of receivers K, any receiver connectivity L <= K, and with caches equipped at all transmitters and receivers. The cache placement phase adopts a file splitting strategy tailor-made for the partial receiver connectivity. Via the aid of virtual receivers, the proposed delivery strategy exploits coded multicasting gain by XOR combining and transmitter coordination gain by interference alignment. In the special case when L is a divisor of K, our NDT results are directly applicable to K x K partially connected circular interference networks.