Cross-Layer Optimization for Opportunistic Multi-MAC Aggregation

In this paper, we describe a RAT (radio access technology) agnostic approach referred to as OMMA (Opportunistic Multi-MAC Aggregation) that can aggregate multiple RATs operating over independent spectral bands. Aggregation and/or traffic shaping is performed above the air interface protocol stacks but below the IP layer. We investigate the problem of minimizing the average packet latency (the sum of queuing delay and serving delay) under certain constraints and propose an algorithm to compute optimal packet distribution ratio across RATs to be implemented by OMMA. Moreover, we statistically characterize the reordering delay for the OMMA system and propose an algorithm to compute a modified optimal packet distribution ratio which minimizes the packet end-to-end delay, i.e., the sum of average packet latency and average packet reordering delay. Finally, some numerical results are presented to study the average packet latency, average packet reordering delay and average packet end-to-end delay for different system parameters.