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EgprsEGPRS sthands for Enhanced GPRS. Also commonly referred to as 'Edge'. EGPRS is an improvement on the GPRS protocol, replacing the GMSK modulation used in GPRS networks with an eight phase phase shift keying modulation scheme (8PSK). This allows for up to three times the throughput of GPRS at the expense of robustness in marginal and poor signal environments. The advertised improvement of EGPRS throughut is three times that of GPRS. To overcome reduced reobustness of 8PSK, EGPRS networks dynamically vary the coding rates to improve robustness at the expense of throughput under marginal conditions. Thus, the full throughput improvements of EGPRS are only to be achieved in good signal environments. In addition to modifying the coding scheme, EGPRS also introduces "incremmental redundancy" to increase the efficiency of retries in marginal conditions, although few networks support this feature as of early 2005. EGPRS also competes agains UMTS. EGPRS is cheaper and simpler to implement, with fewer royalties than UMTS. It can also be deployed in existing spectrum that carriers use for GSM. However, EGPRS cannot deliver the promised bandwidth of UMTS, although it is yet unclear why one needs so much bandwidth on a mobile handset. However, many carriers have sunk billions in UMTS liscenses, and would prefer that EGPRS go away, as EGPRS delivers much of what UMTS is supposed to deliver but without the sacrifices and expenses. As such, EGPRS is a threat to successful UMTS deployment.
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