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 3GPP^Note-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:

http://www.4gamericas.org/index.cfm?fuseaction=page&sectionid=245

• A Sharper EDGE for GSM by Mark Pecen, VP, Research in Motion Limited Available From:

                 http://www.iirusa.com/upload/wysiwyg/2007-U-Div/U2046/Whitepapers/IIR_U2046_Sharper_EDGE_Pecen.pdf

• EDGE Evolution Technology Introduction, Application Note 1MA129 by Rohde & Schwarz

Available From: http://www2.rohde-schwarz.com/file_8617/1MA129_1E.pdf

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

EDGE Evolution - Part 1

Hi All,

Even though the Mobile world is running behind LTE & LTE-A, there should be some concern put on existing mobile operators. In many countries 4G Licenses are preferred to be auctioned freshly to create some additional economy stream for Governments of respective countries.

So there is great possibility that couple of operators to remain with 2G Technologies. Since GSM is the most spread 2G Technology. EDGE is one of the key enhancer rolled out in these networks to cater the Mobile Data service demands.


As per GSMA March,2011 report 531 Networks in 196 countries employed EDGE in their network. 12 more Operators in 2 more counties about to launch.

 

In some of the Asian countries the uptake of mobile broadband in the form of 3G Subscription is not as expected.Even though the growth rate is good, operators cannot invest further in 3G technology various 4G operators are already in completion for the niche "Mobile Broadband" segment which existing players cannot avoid.

Again 4G deployment has its own challenges in the form of Regulatory/Handsets/Frequency. 

 

So the operator who has substantial investment in the 2G form can use EDGE Evolution to address the mass market who are just using ( or starting ) to use data networks for the purpose of social networks/news/sports. This is one of the biggest segment in customers unlike the market segment who are all heavy users with dongles/tablets

In telecom , as in the past every step in telecom evolution has its own  risks and per-requisites.

I will address couple of them in next update along with the argument why EDGE Evolution (i.e. EDGE II) is must as a survival kit for 2G Only operators or even fr the operators who are overlaying a 4G Capable network over their existing 2G / 3G Networks.

Part-2 available here : EDGE Evolution - Part2

Part-3 available here : EDGE Evolution - Part3

Disclaimer Statement - For this Blog & Posts in it

Hi There,

This is a personal weblog developed for discussion within my study group for the Masters Program.The opinions expressed here represent my own and not those of my present/previous university/employer.

In addition, my thoughts and opinions change from time to time as the technology develops and arrival of new solutions in telecom.

If you feel that I should correct some of the posts/statements, please contact my email id. I will be more happy to do it.

Regards

S.Sunil Kumar
sunil_almnthat@yahoo.com

APN Configurational Issues in Android OS Enabled Phones : Part-1

As many of us know, internet & MMS traffic are the most used data service types as of today. Streaming video, Corporate Intranet, Cloud services, VoD are gearing to take the customer experience to new levels . Still there are some of the fundamental issues to be dealt for a brighter win-win situation across the entire ecosystem of mobile telecom industry (Mobile Broadband + Voice) across the globe.

It is evident that offering mobile broadband using “LTE” technology is more efficient then any other existing one at present. LTE networks are mostly being built on existing 3G/2G Core Network infrastructures like SGSN/GGSN by duly upgrading them as MME/SGW respectively.

But the important big question is still on the “UE” Manufacturing.

There are big dilemmas like create only Dongle and move to VoLTE and get voice services or manufacture multi radio support capable handsets or not.

It is well known truth the Frequency Bands going o be one of the deciding factors of these questions.

For an example iPhone 5 supports few LTE Bands. And the handsets available in non US countries too but can it supports the frequency bands of those countries which may allocate different one than US?

http://www.gsmarena.com/apple_iphone_5-4910.php

This is an example of the main topic we are about to step into...APN

What is APN?

As explained in http://en.wikipedia.org/wiki/Access_Point_Name

Access Point Name (APN) is a configurable network identifier used by a mobile device when connecting to a Mobile Services carrier. The carrier will then examine this identifier to determine what type of network connection should be created, for example: what IP addresses should be assigned to the wireless device, what security methods should be used, and how or if, it should be connected to some private customer network.
More specifically, the APN identifies the packet data network (PDN), that a mobile data user wants to communicate with. In addition to identifying a PDN, an APN may also be used to define the type of service, (e.g. connection to wireless application protocol (WAP) server, multimedia messaging service (MMS)), that is provided by the PDN. APN is used in 3GPP data access networks, e.g. general packet radio service (GPRS), evolved packet core (EPC).

So it is evident that APN helps the network to determine proper routing of the data packets.

Nokia, Sony, Sony Ericsson, Samsung (Bada-OS) & iPhone  (iOS 6) - All of them support multiple APN-Application Context Names. But phones loaded with android OS offers only one APN definitions and which is applicable for any applications invoked in that particular phone as explained simply in the following Figure-2.

 

Figure-1 3GPP R8 Standard Architecture

 

Figure-2 Dats Service Types & APN Usage

Impact 1: Unnecessary load for GGSN in finding the proper route towards MMSC/Other services.

Solution 1: Based on the specific MMSC Proxy address, DNS can provide the routing,

Disadvantage: DNS Capacity is compromised.

Impact 2 : QoS treatment will not be proper. QoS to be differentiated based on invoked service based on the invoked service rather than applying a standard profile HLR passes differential QoS to SGSN if subscribed differently. Even SGSN itself can alter the QoS according the requested APN. But not as per the requested “SERVICE” if that comes via the same APN. SGSN don’t have the ability to treat a particular type of traffic within an established DATA PIPE (i.e. GTP Tunnel).

Disadvantage: Customer experience compromised. Normally for such bad performances the network will be vivtim to pay the price whereas the issue lies somewhere else which is not easy for all to understand.

Solution 2: It is important that Android Platform to have multiple APN Definition capability as per 3GPP standard and each of the service/application should have the freedom to choose appropriate APNs based on manual /OTA Push configurations.


This discussions is more about QoS handling in the Um/Uu & Gb/IuPS interface.

Part 2 : End and Conclusion

An Evolution in US Mobile Broadband Industry - Lightsquared -> Ligado

Update on 23rd-April-2017 :-


Good to see that the Lightsquared is coming out of bankruptacy and emerging with new focus.
They have renamed as Ligado and expected to be operational soon...

For more details http://ligado.com/

http://www.fiercewireless.com/wireless/lightsquared-rebrands-as-ligado-networks-but-spectrum-plans-remain-cloudy

An Update on 30th-Oct-2012 :-

LightSquared booked Chapter-11 Bankruptacy

Sprint broke the deal it has signed with LightSquared for network sharing..

And so many other issues... Looks like LightSquared ran in to issues with GPS operators due to neighboring frequency band and also some other arguments [ Ref : LightSquared News Site]

Real Issue : LightSquared was intended to use its L-Band which is neighboring the GPS band.Since the GPS systems don't have the ability to ignore nearby LTE band frequency.There is no clarity of who is at fault.

Initial Post by 17th June-2012 :-

While reading Deepak Gurang's Blog, 

Ref  : http://4gmobile-renold.blogspot.in/2011/01/lightsquared-gets-green-light-to-build.html

I came across an article about LightSquared A US Company who recently got approvals to deploy LTE Network using terrestrial & Satellite Networks.

Ref : http://www.lightsquared.com/what-we-do/

The concept of using Satellite for telecom services always  points toward the "Latency" issue.

Reference : http://www.satellitetoday.com/via/features/Minimizing-Latency-in-Satellite-Networks_31811.html

Currently there are only few such satellite networks survives with good customer base. Ex : Thuraya/Inmarsat. Thuraya has more voice traffic while Inmarsat has more data traffic. [ Not sure about the current Status @ 2012]

The latency observed in satellite networks with satellites positioned at GEO Orbit is ~ 280 ms.

Ref : http://www.satsig.net/latency.htm

So with this roadblock, LightSquared may not be able to offer a superior quality VoIP service, but a network may serve well for the demanding WEB & Video Streaming services.


Additionally they are about to run a terrestrial LTE Network also. 

The questions which popped up are....

• How they will be able to direct the subscriber traffic demand accordingly to serve various services ?
• How they are going to design the end user terminals which has to work both in terrestrial and Satellite network ?

Also they are revolutionizing the operating model by doing only wholesale business. It is good for the country to make the broadband market boom.

This model opens up a great deal in US consumer market and helps variety of companies to leverage the opportunity to reach potential customers of their product in a better way rather than usual Newspaper/TV ad models which is is in decline as of now due to the growing communication device oriented lifestyle.

The day is not far the a couple of  countries can and join together to build a network which can be sold on wholesale models to their respective operators/MVNO operators.

The ownership of telecom business slowly drifting away from traditional operating models.