No abstract

In this paper, we introduce a new Adaptive Physical Resource Block Design for Enhancing Voice Capacity over Long-Term Evolution (LTE) Downlink in Professional Mobile Radio (PMR) Context. In this method, we reorganize the structure of the Physical Resource Block (PRB) to optimize the voice capacity of LTE downlink in the PMR Context. Available PRBs in each subframe is reorganized into a number Sub Physical Resource Blocks. The number of control symbols can be selected flexibility. The proposed method allows reducing both data overhead and control overhead issues for Voice over LTE downlink in PMR context. On average, the voice capacity gain were shown to have about 117.2% in comparison with the standard LTE.

In this paper, we introduce a new Code Division Multiple Access (CDMA)-Orthogonal Frequency-Division Multiplexing (OFDM) combination method for Enhancing Capacity of Voice over LTE (VoLTE) Uplink in PMR context. In this method, voice payloads of different User Equipments (UEs) having the same Modulation and Coding Scheme (MCS) can be spread by different orthogonal codes and mapped to the same set of resource elements. The selection of spreading factor allows a maximum reduction of the difference between the LTE Uplink packet size and PMR voice payload. The proposed method allows reducing both data overhead and control overhead issues for VoLTE uplink in PMR context. The CDMA-OFDM combination method gives a significant increasing in capacity of VoLTE uplink over PMR context. In the best case, the proposed method can improve the voice capacity by the factor of 7 in comparison with the standard LTE.

Despite the fact that Long Term Evolution (LTE) supports high-speed data transmission and supports different packet sizes by using Adaptive Modulation and Coding (AMC), LTE is not yet optimized for low bit rate voice communication, especially in case of using LTE in Professional Mobile Radio (PMR) context. In LTE, one pair of Physical Resource Blocks (PRBs) is the smallest User Assignment Unit. However, the smallest LTE packet size is still too large in case that low bit rate voice communication is transmitted in high Modulation and Coding Scheme (MCS). This reduces the voice capacity over LTE in PMR context. Therefore, we propose a new Multi-users Multiplexing Radio Voice Transmission method for enhancing voice capacity over LTE in PMR context. In this method, voice packets from different users are multiplexed into one LTE packet in the downlink transmission. In this paper, we propose a new scheduling method that can be used to transmit the multiplexed packets to corresponding users. This paper gives also a novel algorithm for classifying and grouping voice packets of mobile users having different MCS values. In case of low and medium number of users, the results show that the average voice capacity gain of the proposed method can rise up to 89.6%. In case of high number of users, the proposed method can improve the voice capacity by factor of 6.5.