Study of EDGE technology

1. EDGE TECHNOLOGY

2. INTRODUCTION
 EDGE is a digital mobile phone technology that allows
improved data transmission rates as a backward-compatible
extension of GSM.
 EDGE/EGPRS is implemented as a enhancement for
2.5G GSM/GPRS networks, making it easier for
existing GSM carriers to upgrade to it.
 EDGE doesn’t requires much hardware or software
changes to be made in GSM core networks.

3. TRANSMISSION TECHNIQUES
 In addition to GMSK, EDGE uses 8-PSK for the upper
five of its nine modulation and coding schemes.
 Triples the data rate offered by GSM.

4. GMSK
 Gaussian Minimum Shift Keying, GMSK, the form of
modulation with no phase discontinuities used to
provide data transmission with efficient spectrum usage.
 GMSK has high spectral efficiency, but it needs a higher
power level than QPSK, for instance, in order to reliably
transmit the same amount of data.
 It has advantages of being able to carry digital
modulation while still using the spectrum efficiently.

5. Waveforms and PSD

6. GMSK Modulation

7. 8-PSK
 8-PSK is usually the highest order PSK constellation
deployed.
 There are 8 different phase changes defined, each phase
change represents the transmission of 3 bits.
 Baud rate is 1/3rd of bit rate for 8-PSK system.

8. Constellation Diagram

9. Waveforms of PSK

10. Transmitter Block Diagram
Serial to
parallel
converter
 Sine wave
generator
phase
controlled
by VA
b(t)
Digital to
analog
Digital
input
converter M-ary PSK
output
Analog voltage
VA
N bit symbol
0
1
2
N-1

11. Advantages of 8-PSK
 Bandwidth reduces as no. of bits/symbol increases.
 It gives better performance where the signal
amplitude varies due to the characteristics of the
transmission medium.

12. Disadvantages of 8-PSK
 Probability of error increases as no. of bits/symbol
increases.
 Transmitter and receiver are very complex.

13. EDGE MODULATION AND CODING SCHEME
The channel encoding process in GPRS as well as
EGPRS/EDGE consists of two steps:
1. first, a cyclic code is used to add parity bits, which are
also referred to as the Block Check Sequence,
2. followed by coding with a possibly punctured
Convolutional code.

14. CYCLIC BLOCK CODES
 A linear (n, k) code is called a Cyclic code if all
cyclic shifts of a codeword are also a codeword.
U ( u , u , u ,..., u
)
“i” cyclic shifts of U

( , ,..., , , , ,..., )
1 1 0 1 2 1
( )
0 1 2 1
     


n i n i n n i
i
n
u u u u u u u
U
Example:
U
(1101)
(1) (2) (3) (4)
    

(1110) (0111) (1011) (1101)
U U U U U

15. BLOCK DIAGRAM : CONVOLUTIONAL CODING
Information
source
Rate 1/n
Conv. encoder
Modulator
1 2 ( , ,..., ,...) i m  m m m
Information
sink
Rate 1/n
U  G(m)
U U U U

U u ,...,u ,...,u
Conv. decoder
( , , ,..., ,...)
1 2 3
i

Codeword sequence
i i ji ni
n
Demodulator

Input sequence
1

Branch word ( coded bits)

ˆ ( ˆ , ˆ ,..., ˆ ,...) 1 2 i m  m m m
Z Z Z Z
( , , ,..., ,...)
1 2 3

Z 
 1

outputs per Branch word
Demodulator outputs
for Branch word
received sequence
n
i ji ni
i
i
i
Z 
z ,...,z ,...,z
Channel

16. CODING SCHEMES

17. POPULATION COVERAGE BY TECHNOLOGY

18. MAXIMUM DOWNLOAD AND UPLOAD SPEED
 EDGE can carry a bandwidth up to 236 kbit/s for 4
timeslots.
 It provides data rates in the order of 200 kbit/s.

19. EDGE SPECIFICATIONS

20. ADVANTAGES
 It only requires program upgrade of some network
elements.
 EDGE can transmit and receive data three times as fast
as a normal GPRS connection.
 90% of the existing operators using the GSM networks
provide internet access through EDGE.

21. DISADVANTAGES
 The hardware part of MS is to be replaced.
 It consumes much of the battery power.

22. APPLICATIONS
 Mobile Internet access
 Wireless access to databases
 Electronic banking
 Electronic payment
 Messaging
 Security/supervisory systems
 Reservation system (e.g. hotel, theater, flights)
 Video telephony
 Telescoping

23. REFERENCES
• Wireless Communications & Networking
By Vijay Garg, Morgan Kaufmann Publication, 2009 Edition
• M. Kottkamp, “EDGE Evolution”, 2008
• Articles- EDGE, Phase Shift Keying, Convolutional Code by Wikipedia
• GMSK- radio-electronics.com

24. THANK YOU