Edge technology

[seminar class]

[attachment=10100]
EDGE
EDGE is an extension of GPRS.
The 4 GPRS Coding Schemes are extended with
9 new EDGE Modulation and Coding Schemes
What is EDGE for ?
Improves spectral efficiency
New EDGE Modulation & Coding Schemes
• GSM/GPRS uses GMSK modulation (Gaussian Modulated Shift Keying) and 4 Coding Schemes are defined in GPRS : CS1 to CS4.
• EDGE introduces a new modulation : 8PSK (8 Phase Shift Keying).
– 8PSK defines 8 states of the radio signal instead of 2 for GMSK.
– 3 bits can be coded with 8PSK instead of 1 for GMSK.
Backhaul Update for EDGE Throughput
• Higher coding schemes for increased user data throughput drives higher backhaul requirements.
• Backhaul increased in 64kbps (DS0) increments for Abis.
• Backhaul increased in 16kbps (¼ DS0) increments for Agprs.
Dynamic Abis
• Main TS : 16k TS used for voice, data circuit and GPRS dedicated to one radio TS,
• Joker TS : each TDMA is associated to a set of 64K TS
– each 64k TS is divided in 16 k TS
– these 16k TS used only for EDGE,
– dynamically shared between all radio TS of the TDMA.
• Each radio frame is managed by :
– the main TS,
– n joker TS, according to
the PDU size.
– each joker frame indicates the associated main TS at each ccurrence
Cell throughput distribution
• Throughput highly depends on radio quality (distance from cell center and interferences).
Link Adaptation adapts the MCS based on those variable radio conditions