Eric Georgeaux

Scheduling for Multi-users Multiplexing Radio Voice Transmission for enhancing voice capacity over LTE in PMR context

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.

Architecture for Multi-users Multiplexing Radio Voice Transmission for enhancing voice capacity over LTE in PMR context

Recently there has been a great interest in how to apply Long Term Evolution (LTE) in Professional Mobile Radio (PMR) context, which is used for public safety work. However, LTE is not yet optimized for low bit rate voice communication. The smallest LTE packet size is still too large in case that low bit rate voice communication is transmitted in high quality channel. This is one of the main challenges for effectively applying LTE in PMR context. Therefore, this paper presents a new architecture for Multi-users Multiplexing Radio Voice Transmission for enhancing voice capacity over LTE in PMR Context. This architecture allows reducing the difference between the LTE packet size and voice payload by multiplexing voice packets from different users into one same LTE packet in the downlink transmission. In this architecture, the multiplexing size can be modified according to the Modulation and Coding Scheme (MCS), the payload of users and the LTE bandwidth. Our simulation results show that in the best case, our proposed method can achieve a gain up to 650 % in the voice capacity gain as compared to the standard LTE.

D2D broadcast communications for 4G PMR networks

As professional mobile radio (PMR) networks evolve to a new generation based on Long Term Evolution (LTE), a new direct communication mode needs to be developed. Not only in PMR networks, but the increase of proximity services due to the explosion of the internet of things bring us to a new communication paradigm. The PMR users have very specific requirements and one of those is the ability to communicate in a direct way with all the group members, even in out-of-coverage scenarios. In the current PMR standards, communication degradations due to collisions can occur when there is no infrastructure available, especially in dense scenarios. In this article, we propose a mechanism that allows device-to-device (D2D) broadcast communications, even in out-of-coverage scenarios. The mechanism presented hereafter improves the data rate compared to the current PMR mechanism, by reducing the number of collisions using the LTE physical resource block (RB) structure.

Adaptive physical resource block design for enhancing voice capacity over LTE network in PMR context

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 are reorganized into a number of Sub Physical Resource Blocks. The number of control symbols can be selected flexibly. The proposed method allows reducing both data overhead and control overhead issues for Voice services over LTE downlink in the PMR context. On average, the voice capacity gain were shown up to 117.2% in comparison with the standard LTE.

CDMA-OFDM combination method for enhancing capacity of voice over LTE Uplink in PMR context

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.

RNTI Aggregation for Multi-Users Multiplexing Radio Voice Transmission for Enhancing Voice Capacity over LTE in PMR Context

Voice capacity over Long Term Evolution (LTE), despite the fact that LTE supports high-speed data transmission, is still low due to the large data and control overhead. This is one of the primary obstacles to apply LTE to Professional Mobile Radio (PMR) system because the voice capacity is one of the main requirements of the public safety network. To overcome this issue, there are several studies aiming at reducing one of the two overheads in LTE, data or control. However, in most cases the voice capacity gain can only be improved by both reducing data and control overhead. This is because these two factors are strongly related in carrying out the resource allocation. In [1], we proposed a Multi-users Multiplexing Radio Voice Transmission method. This method clusters voice packets from different users into one same LTE packet in the downlink transmission for reducing the data overhead caused by the difference between LTE packet size and the PMR voice payload. This paper presents a new Radio Network Temporary Identifier (RNTI) aggregation method to solve the control overhead issue for the multiplexing scheme of Voice over LTE (VoLTE) in PMR context. Our method uses Physical Downlink Control Channel (PDCCH) channel with high format, created by the aggregation of PDCCH channels with low format, to transmit several RNTIs of different User Equipments (UEs) in a same multiplexing group. The number of RNTIs in one PDCCH is calculated to ensure that there is no increase of Bit Error Rate (BER) for receiving PDCCH channel. The results show that the RNTI aggregation method can increase the control capacity of the multiplexing scheme up to 170%. The combination of Multi-users Multiplexing Radio Voice Transmission method and RNTI aggregation method allows reducing both data and control overhead of VoLTE in the PMR context.

An energy efficient D2D LTE structure for PMR based on FlashLinQ

Device-to-device communications are one of the most important challenges for cellular mobile communications. Professional Mobile Radio (PMR) networks could change the current standard for a new one based on 4G, when this type of communications will be included. PMR users such as police, fire brigades also use the D2D communications in under coverage and out of coverage scenarios. This type of users also operate with D2D broadcast group communication in this scenarios, transmitting at its maximum power to be understood by all group members. In this paper we present a new D2D broadcast mechanism based on FlashLinQ that will allow seamless communications in under coverage and out of coverage scenarios reducing the total energy consumed by the terminals. To that endm we implement a collision avoidance mechanism as well as power control mechanism to avoid wasted energy and thus, improving terminals energy efficiency (EE) while the communications are still guaranteed for all group members.

From DMO to D2D

Direct communications have been used for long time in PSNs. Today, due to the expectations of the transmitted traffic through the network and the popularity of proximity services, direct communications may also be present in the future generation of public cellular networks.