The Design of Transport Block-Based ROHC U-Mode for LTE Multicast

One important issue that confronts multicast service is multiple-user satisfaction under dynamic channel conditions over cellular networks. In practical Long Term Evolution (LTE) networks, a key mechanism that affects the transmission efficiency and robustness for each user is RObust Header Compression (ROHC). In this work, we improve the transmission performance of multicast aiming at satisfying all the users with a trans-layer design scheme. We first establish a practical system model for trans-layer multicast networks, with transport blocks (TBs) as the transmission units. Focusing on the optimization of ROHC, we formulate a novel trans-layer control framework in terms of partially observable Markov decision process (POMDP) to maximize the total number of successfully received payload bits among all users in one Multimedia Broadcast Multicast Service (MBMS). To address the complexity issue of the rigorous POMDP formulation, we further develop an Instantaneous Marginal Belief (IMB) policy algorithm to handle multiple-user. Our numerical results demonstrate substantial improvements by the proposed policy.