With various packet-switched networks coming to the fore, real-time services like voice and video, transmitted traditionally using circuit-switched bearers, can have limited capacity due to the limited availability of resource-granting control channels. Such packets are frequent and require more grants compared to other services like FTP. To compound the issue, often these packets are large in size compared to available resources for allocation. To improve the capacity of real-time communication over LTE (-A), various scheduling methods are being studied. However, often the packet sizes are unaccounted for by these studies. This work deals with the development of semi-persistent scheduling (SPS) algorithms based on wide-band time-average SINR information for resource allocation to voice traffic users, with a focus on large packets. A comparative study between dynamic scheduling (DS) and developed SPS algorithms is done to determine the suitable scheduling mechanism for voice packets transmission over LTE (-A) systems in the downlink.