Fundamental Limits of Wireless Caching Under Mixed Cacheable and Uncacheable Traffic

We consider cache-aided wireless communication scenarios where each user requests both a file from an a-priori generated cacheable library (referred to as ‘content’), and uncacheable ‘non-content’ message at the start of transmission session. This scenario is easily found in real-world networks, two types traffic coexist share limited radio resources. focus on single-transmitter, single-antenna networks with receivers, channel modelled by degraded Gaussian broadcast (GBC). For this setting, we study delay-rate trade-off, which characterizes content delivery time non-content rates that can be achieved simultaneously. propose scheme based separation principle, isolates coded caching multicasting problem physical layer problem. show separation-based sufficient for achieving information-theoretically order-optimal performance, up multiplicative factor 2.01 time, when working generalized degrees freedom (GDoF) limit. further achievable performance near-optimal after relaxing GDoF limit, additional additive 2 bits per dimension rates. A key insight emerging our some considerable amounts communicated while maintaining minimum absence messages; compliments ‘topological holes’ arising asymmetries gains.