Shkumbin Hamiti

Delay analysis for IP speech over GPRS

This paper presents a delay analysis for G723.1 voice packets, which are transmitted over an empty (low load) GPRS network. The work concentrates on the delays of the user plane in a conversation type voice service, which is transferred with RTP/UDP/IP protocols. Audio streaming and voice transmission without RTP/UDP/IP protocols are not considered. Transmission errors, call setup and release procedures are not taken into account.

EDGE circuit switched data-an enhancement of GSM data services

One step in the evolution of the real-time GSM services is the enhanced circuit switched data (ECSD) which is being developed in ETSI as a GSM Phase 2+ work item (EDGE Phase 1) parallel to the Enhanced General Packet Radio Service (EGPRS). The ECSD radio interface deploys 8-PSK modulation in addition to GMSK and thus enables higher data throughput per time slot. This paper gives an overview of the ECSD concept and examples of applications that it supports. The focus is in the link level and the radio network level performance of different ECSD data rates in various test environments. It is shown that by utilising the proper link adaptation mechanism, even demanding transparent high data rate services, like video, can be supported with a good coverage.

Enhanced circuit switched data for real time services over GSM

The deployment of the HSCSD (high speed circuit switched data) is starting in GSM networks. This brings multislot capability to GSM and significantly enhances the available data rates together with the introduction of the 14.4 kbps per time slot data rate. The next step in the evolution of the real-time GSM services is the enhanced circuit switched data (ECSD) which is being developed in ETSI as GSM Phase 2+ work item (EDGE Phase I) parallel to enhanced general packet radio service (EGPRS). The ECSD radio interface deploys 8-PSK modulation in addition to GMSK and thus enables higher data throughput per time slot. The ECSD type radio interface can also be seen as a candidate in the development of real-time services for the evolving mobile networks. This paper focuses on the ECSD concept and presents its essential features as they are defined at the moment, before finalisation of the standard.

Handover of packet-switched services in GERAN A/Gb mode

Due to strict quality of service requirements on low latency and packet loss, real-time packet-switched (PS) services require a minimal service interruption on the data transfer during cell change. Existing GPRS cell change mechanisms with network assisted cell change (NACC) enable a theoretical minimum service interruption of 0.7-1.2 second, while real-time PS services of conversational class do not tolerate a service gap longer than 0.15 seconds. Therefore in GERAN A/Gb mode a PS handover procedure is being designed to allow for conversational services in GPRS that would improve the network performance for any PS service. PS handover follows the GSM circuit-switched handover principle of allocating radio resources in the target cell prior to changing cell. In this paper PS handover procedure is described and its performance evaluated in terms of service interruption by means of network simulations

Radio resource control for GSM/EDGE Radio Access Network (GERAN)-inter radio access technology and inter-mode procedures

The 3GPP Release 5 will specify a GSM/EDGE Radio Access Network (GERAN) which can connect to 3G mobile core network (CN) through the Iu interface. The new architecture implies significant modifications to the GERAN radio protocols. This paper focuses on radio resource control (RRC) procedures, especially on the new defined inter radio access technology procedures between GERAN Iu mode and UMTS Terrestrial Radio Access Network (UTRAN) or inter-mode procedures between GERAN Iu mode to GERAN A/Gb mode in Release 5.

Performance of streaming services in GERAN A/Gb mode

The ongoing growth of GSM users as well as the increasing availability of IP based real-time services leads to the necessity for enabling real-time services in GSM/EDGE radio access network (GERAN) A/Gb mode. In this paper, the performance of real-time services, specifically streaming services in GERAN A/Gb mode is evaluated by means of simulation and live network measurements. The most critical GERAN A/Gb mode procedures for the performance of streaming services are cell and routing area changes. This is due to data transfer interruptions, which cause delay variation and packet losses. The presented results show that streaming services are feasible in GERAN A/Gb mode and that the performance can be improved further with sizing of the client buffers according to the delay introduced by the cell/routing area change taking into account the effect of reduced radio quality at the cell border.