Uplink capacity-delay trade-off in hybrid cellular D2D networks with user collaboration

Device-to-device (D2D) communications and open-access small cells can be leveraged to off-load delay-insensitive and cost-sensitive data from burdened cellular networks. The resulted system is called hybrid wireless networks, whose capacity and delay performance have been studied extensively under a popular information-theoretic framework called scaling law analysis. Most studies, however, do not take into account realistic aspects of interference accumulation and queuing delay, and therefore may lead to over-optimistic results. Moreover, focusing on the average measures, existing works fail to give finer-grain insights such as the distribution of delays. This paper proposes an alternative analytical framework based on queuing theoretic models and stochastic-geometry based physical interference models. This new framework allows us to fully characterize the delay distribution in the transform domain and pinpoint the impacts of user and base station densities, transmit power, user mobility, and packet size on the capacity-delay trade-off.