Enhanced Data rates for Global Evolution (EDGE) - Wireless Communications

Wireless Communications - GSM | GPRS | 3G/UMTS | EDGE

Wireless Communications Solutions

Enhanced Data rates for GSM Evolution (EDGE)

Overview | Reverse/Forward Process | Library Components

EDGE - Overview

Beyond GPRS, EDGE takes the cellular community one step closer to UMTS. It provides higher data rates than GPRS and introduces a new modulation scheme called 8-PSK. EDGE is also being adopted by the TDMA community for their migration to UMTS. Nuntius has solutions for the EDGE handset functions to help reach handset deployment quicker. For more information, contact Nuntius Systems, Inc.

Data rates:

384 kbps and above

Channel coding

Outer block coding
Inner Convolutional coding
Interleaving scheme for error bursts

Modulation

GMSK (Gaussian Minimum Shift Keying)

8-PSK (Phase Shift Keying)

Multiple Access
Combination of TDMA & FDMA

Transmit Frequency bands

Mobile station
Base station
Uplink
Downlink
Reverse ch. 890 - 915 MHz
Forward ch. 935 - 960 MHz

Duplex seperation 45 MHz

RF carrier spacing 200 kHz

Number of TDMA slots on each carrier 8

Channel allocation 1 to 8 time slots per TDMA

One time slot (Physical channel) 0.577 ms

Frame Interval: 4.615 ms

Asymmetric data traffic different time slots for Uplink and downlink

Frequency Hopping: 217 hops/s (slow)

Equalizer: 16 盜 time dispersion

Connectivity: Packet switched data networks such as IP and X.25

Asymmetric data traffic different time slots for Uplink and downlink

Modulation

Gateway GPRS Support Node (GGSN) and
Serving GPRS Support Node (SGSN)

Channel coding schemes :

CS-1 through CS-4, MCS1-MCS9

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EDGE - Reverse/Forward Link

Composition

Packet data traffic channels
Packet common control channels
Packet dedicated control channels

Transmission

Channel coder

Block encoder

Precoding of Uplink Status Flag (USF)

Add Tail bits

Convolutional encoder

Puncturing

Channel coding schemes(in addition to GPRS)

Scheme
Peak Rate per slot (kbps)
RLC Block size Code
Rate

MCS-1
MCS-2
MCS-3
MCS-4
MCS-5
MCS-6
MCS-7
MCS-8
MCS-9
GMSK
GMSK
GMSK
GMSK
8-PSK
8-PSK
8-PSK
8-PSK
8-PSK 8.8
11.2
14.8
17.6
17.6
17.6
17.6
54.5
59.2
.5
.66
.75
1.0
1.0
.37
.49
.76
1.0

Reception

GMSK Demodulator
Viterbi equaliser
Deinterleaver
Viterbi decoding

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EDGE - Standard Library Functions

The following is a list of the standard library functions to perform the various aspects of GPRS. These functions can be implemented in a DSP or the ARM RISC architecture. In general, the layer 1 functions are usually implemented in the DSP while upper layer protocols such as SNDCP are implemented in the ARM RISC. The channel models are used for simulating the channel operating environment and are not a function that would be implemented in a mobile handset or base station.

Channel codes
Block encoder
Fire coder
Precoding of uplink status flags
Convolutional coder (1/2, 2/3 and 3/4)
Puncturing

Interleaver / deinterleaver

Interleaver of depth 4 / deinterleaver

Channel models

Rayleigh distribution

Rice distribution

Propogation models for urban and rural areas

Modulation / Demodulation

GMSK modulation / demodulation

Channel Decoder

Viterbi decoder

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