Cross-layer resource allocation for mixed tactile Internet and traditional data in SCMA based wireless networks

The tactile internet requires an ultra short end-to-end (E2E) latency of about 1 ms and is proposed as one of the fifth-generation (5G) wireless cellular network applications. In a typical 5G framework, inclusion of tactile data that imposes different delay requirements than traditional data to the system, makes the system implementation more challenging. This paper is concerned with resource allocation to maximize the uplink sum rate of traditional data while satisfying the delay requirements for tactile data. To do so, we propose a practical model for delay in which the queuing delay both at the source and the base station is considered. We use sparse code multiple access (SCMA), one of the candidate multiple access techniques in 5G cellular network, in our system model. Consequently, for a given number of traditional data streams, we can quantify the reduction in the traditional data sum rate caused by increasing the number of tactile data streams. In addition, we investigate the effect of quality of service coefficient, referred to as θ on the uplink sum rate of traditional data and show that there is a threshold behavior such that if θ gets larger than a certain value, the sum rate of traditional data drastically decreases toward zero.