Study on resource allocation for VoIP traffic with subframe bundling in LTE uplink

In order to support efficiently Voice over IP (VoIP) traffic using semi-persistent scheduling in the Long-Term Evolution (LTE) uplink, frequency hopping (FH) should be applied to obtain a frequency diversity gain. In addition, subframe bundling (SFB) is also effective for improving the received signal quality of users in the vicinity of the cell edge. However, since a resource block (RB) allocation for the SFB with FH becomes widely dispersed, it might be difficult to utilize fully and densely whole RBs in a system bandwidth when simultaneously allocating the RBs to both users with and without employing SFB. Therefore, in this paper, two methods that enable dense RB allocation are proposed, which are referred to as SFB priority allocation and interlaced allocation. These two methods are evaluated in a system level simulation in a mixed traffic scenario of VoIP and non real-time traffic, taking into account the constraint of signaling overhead. Simulation results show that the two methods can increase the VoIP capacity by about 10% compared to a straightforward manner that simply allocates RBs based on the frequency index of RBs regardless of whether or not SFB is applied. In addition, it is shown that the Interlaced allocation can further increase the VoIP capacity compared to SFB priority allocation.