TCP PERFORMANCE OVER EGPRS/EDGE

Abstract

Enhanced Data rates for GSM Evolution (EDGE) is a radio access technology capable of providing wireless Internet access services. Enhanced General Packet Radio Service (EGPRS) is the packet mode of EDGE, designed to provide reliable, enhanced data rate services under all channel conditions using high-level modulation and link adaptation techniques. This paper evaluates the performance of TCP over EGPRS using the Network Simulator (ns) simulation tool. Under good channel conditions, EGPRS is capable of achieving data rates of 240 kbps compared to 171 kbps provided by GPRS. Link adaptation based on Carrier-to-Interference ratio (C/1) estimation selects optimal coding schemes under good channel conditions, while the Block Error Rate (BLER) approach selects optimal coding schemes under poor channel conditions. A hybrid link adaptation scheme derived from both schemes is able to select the best coding scheme to achieve optimal throughput performance under most channel conditions.