Showing posts with label EDGE II. Show all posts
Showing posts with label EDGE II. Show all posts

Thursday, October 25, 2012

EDGE Evolution - Part 4


Refer - EDGE Evolution - Part 1, Part 2 & Part 3


Multi Carrier for EDGE II

As explained in EDGE Evolution- Part-2 post , by using 

  • EGPRS-2A downlink: 8-PSK+16/32QAM+Turbo Codes
  • EGPRS-2A uplink: 16QAM
  • EGPRS-2B downlink: QPSK+16/32QAM+Turbo Codes+Higher Symbol Rate
  • EGPRS-2B uplink: 16/32QAM+Higher Symbol Rate  

So by enabling 5 Time slots we can achieve a data rate of 5 * 118.4 Kbps = 592 kbps.




Figure 1 : 2 GSM Carriers with 5+5 EDGE Capable Channels


By bringing the Mulitcarrier [ Note 1 ] concept  to EDGE II enabled GERAN Networks we can catapult the data rate from 592 to 1184 Kbps. Which is more than enough for mobile users with constant mobility and who are more interested in social networks/news/sports/mails etc. which are can be executed at the convenience of a good 1 Mbps network. This is the segment which is still untapped and the revenue growth can be achieved greatly with this big base than any other corporate/HNI  segment customers in terms of Data Services.


Note 1 :  DC-HSPA Dual Carrier standardized as part of 3GPP R8 released by 2009. Multi-Carrier HSPA Evolution by Mats Blomgren, Anders WallĂ©n of Ericsson Research,Stockholm/Lund, Sweden



2G to 4G Technology/Architecture Evolution

Similar like the 3G to 4G  Technology/Architecture Evolution , there should be some enhancements as like Direct Tunneling & Flat Architecture as shown in the Figure 2 & 3 below.The operators gets the benefit of proper evolution path with minimum impact to customers and also the core is getting fully evolves as in SAE (EPC) standards and ready for LTE Overlaying.

Flatter architecture means some reduced latency & independent capacity enhancement in network elements.

Figure 2 : 3G to 4G Technology/Architecture Evolution 

Figure 3 : 2G to 4G Technology/Architecture Evolution

BSSAP => RANAP

Also it will be better to use RANAP protocol between BSC and SGSN [ Also between BTS & SGSN ] at a later stage.This will help to leverage the existing ready to use platforms like MME/SGW/PGW which are supporting 3G protocols already as part the 3G to 4G Evolution as shown in Figure 2.

Comments from Friends & Critics are welcome.

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Sunday, October 14, 2012

EDGE Evolution - Part 3



Important Enhancements during GPRS to EDGE/EDGE II Evolution


Post the introduction of EDGE/EGPRS operators & vendors observed that the demand is further raised than the current capacity which eventually triggered the 3rd Generation Mobile telecom services roll out. But some enhancements were inevitable on existing infrastructure which are supporting GPRS/EDGE.

As part of 3GPP R4 review, Gb over IP has been inducted as part of the standards. This Ip-fication step also helps to improve the throughput capacity of Gb interface due to IP Link’s nature of flexibility in capacity growth. Additionally IP technology helps the fast processing of user data packets more efficiently in terms of speed then legacy FRAME RELAY interfaces used earlier in Gb interfaces.FR required extensive hardware and lacked the flexibility in handling growing capacity.


Post 2001, all the base stations manufactured were enabled to support EDGE II (i.e. EGERS 2A & B). Only software upgrade is required to support the Evolved EDGE.

Only handsets are needed to be upgraded to support the feature.         

Figure 1 : 3GPP R4 Standard PS Core Architecture


Figure 2 : 3GPP R4 Gb over IP

Figure 3 :BTS Support for EGPRS2 A & B
  Figure 4 : 3GPP R8 Abis over IP



When we have all the interface on IP technology and only Abis interface in traditional TDM based 2 Mbps PCM type interface, then that will be the only inefficient transport system in the network. 3GPP has already given a recommendation as part 3GPP R8 to replace that as IP technology. It took time for 3GPP to release the recommendations due to the fact that most of the networks Voice network traffic were still carried on TDM interfaces at Abis interface. Once the IP-fication thinking started to come in to picture complete IP-fication is must in Abis interfaces also to support a greater efficiency in Access Transport Network. 

It was not the BTS/BSCs capability made the delay, it was more of wait on efficient transport networks connecting them.

References : 



ETSI - A-interface over IP study Available from:

3GPP - A-interface over IP study (AINTIP) Available from:

Development Progress of Evolved EDGE by ZTE Available from:

Ericsson’s IP-based BSS and radio network server by Niilo Musikka and Lennart Rinnb.ck Available from:
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Thursday, October 11, 2012

EDGE Evolution - Part 2

Kind of Prequel to my earlier post EDGE Evolution - Part 1 

This will revisit the fundamentals of GPRS & EDGE (i.e. EGPRS)....



What is EDGE?

To enable data services in more improved manner to meet the traffic explosion towards internet by mobile phone users, ETSI standardized GPRS - General Packet Radio Service by Release-97 as an overlaid technology on existing GSM networks which was supporting only 9.6 Kbps data rate at that time.Even though HSCSD was in trial and running commercially in few networks, GPRS brought minimum impact to the existing radio access network to achieve higher than HSCSD data rates.Additional network elements (PCU/SGSN/GGSN) were introduced to handle this traffic as shown in Figure 1.

The basic concept is some of the time-slots from GSM TRX is configured as GPRS channels and based on service request they are allotted to users.

Unlike one channel for one voice call concept Note-1, in case of GPRS the engineering is done in a way to allot more channels as per demand for one user. This is already done in CSD/HSCSD implementation. But for GPRS mobile handsets to use specific coding scheme in order to achieve higher data rate compare to traditional 9.6 kbps per channel.

Due to further data services explosion, the demand for more data higher data speed went up then 3GPPNote-2 who succeeded ETSI in standardizations included EDGE in its portfolio as pre-step towards 3G Networks. This was commercially deployed by Cingular in 2003
GPRS was considered as 2.5G and EDGE was considered as 2.75 G.

The date rate was brought from 9.6 kbps (CSD mode) to 43.2 Kbps by HSCSD. Then GPRS brought it up to 80 Kbps using GMSK Coding Scheme and then EDGE brought it to revolutionizing 236.8 Kbps by using QPSK Coding Scheme. Note that all these are theoretical calculations. To achieve this Mobile Equipment, BTS & BSC-PCU required extensive SW & HW upgrades to support the rate. 

Figure 2 shows various formats of data services using GPRS/EDGE network.

Figure 3 & 4 shows the data rates & Modulation schemes used by GPRS/EDGE Networks.

This also pushed the Gb interface from conventional FRAME RELAY type link towards IP link to achieve more flexibility, capacity & redundancy. This is the step which laid the foundation for all IP network at a later stage.

Then further 3G was introduced from which the data rate grown from 384 kbps to 42 Mbps and looking at further evolutions like career aggregation etc. Also 4G came in to play and data rate started from 42 Mbps and touching 1.6 Gbps as recently demonstrated by NSN.

Note 1 : Earlier it was one call per one TS then it become 2-HR calls in one channel. There are substantial developments in the form of VAMOS in order to double the capacity once again.

Note 2 : 3GPP is the owner of all developments and standardization authority. It woeks closely with ETSI/ANSI and other regional standardizations bodies.

 Figure 1  GPRS Standard Architecture
 Figure 2  Data Service types during GPRS/EDGE Deployments
 Figure 3  Data rates & Packet Data Technologies



 Figure 4  GPRS & EDGE - Coding Schemes & Modulation Techniques
 


What is EDGE Evolution / EDGE II / Evolved EDGE? 

During the 3G deployment & evolution experience higher order modulation like 16 QAM / 32 QAM were found yielding more benefits in terms of Spectral Efficiency/Higher Data Rate/reduced latency.

Mean time there were many operators left out to run only 2G Networks or a bigger pie of their network is still in 2G mode ( i.e. reasons like due to regulatory/investment/returns etc.). In order to utilize that 2G Network and enable higher speed for customers who actually in no need of 3G+ level speeds, they addressed to Vendors & 3GPP to look at some possibilities on the existing 2G Network evolution (Actually the story even continues post 4G auctions also).

So to achieve spectral efficiency/higher speed/low latency using higher order modulation in EDGE enabled network become the final decision. 16QAM,32 QAM & 64QAM are inducted in EDGE Coding Schemes as part of 3GPP Release-7.


  Figure 5  EGPRS2-A -Coding Schemes & Modulation Techniques
Figure 5  EGPRS2-B -Coding Schemes & Modulation Techniques


EDGE II is split as 2 phases to help operators and vendors to optimize the roll out & investment.EGPRS2A is only software enhancement in BTS & BSC-PCU with addition of HOM-Higher Order Modulation & Turbo Codes.

EGPRS2B is adding HSR-Higher Symbol Rate to increase the data rate from EGPRS2A. HW changes/upgrades required at BSS network to support the same.There is no architectural change from Figure-1.

To Summarize it...

  • EGPRS-2A downlink: 8-PSK+16/32QAM+Turbo Codes
  • EGPRS-2A uplink: 16QAM

  • EGPRS-2B downlink: QPSK+16/32QAM+Turbo Codes+Higher Symbol Rate
  • EGPRS-2B uplink: 16/32QAM+Higher Symbol Rate  

So by enabling 5 Time slots we can achieve a data rate of 5 * 118.4 Kbps = 592 kbps.



References :


  • EDGE Evolution (EDGE II or Evolved EDGE) – Definitions Available From:

  • A Sharper EDGE for GSM by Mark Pecen, VP, Research in Motion Limited Available From:
  • EDGE Evolution Technology Introduction, Application Note 1MA129 by Rohde & Schwarz



GSM/EDGE: evolution and performance by Mikko Saily, Guillaume S´ebire ,   Eddie Riddington.
 
         Pages: 155,160 & 165
        
Available From:
Google Books for reference / Wiley Books



Important Enhancements during GPRS to EDGE/EDGE II
Comparison of data rate & latency


Some enhancements that can be part of EDGE II
Why EDGE II is needed now? and for whom?

Will be on next post/s.....



Continued in EDGE Evolution - Part 3


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