Reserved Cell in 3GPP UMTS Network

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What is a reserved cell? How to check if 3GPP cell is reserved?

UMTS

A cell is reserved if it is indicated as reserved in RRC System Information Block type 3.

Following exceptions to these definitions are applicable for UEs:

  • Camped on a cell that belongs to a LA that is forbidden for regional provision of service, and during emergency calls.
  • As an outcome of the manual CSG selection procedure the UE is allowed to access an acceptable cell which fulfils the cell selection criteria and is not barred or reserved for operator use for UEs not belonging to AC 11 or 15 and inform NAS that access is possible (for location registration procedure).

How to know if cell is reserved?

Use 3GPP Decoder to decode System Information Block 3 (SIB 3).

  • Check for Cell Access Restriction information element
  • Cell Access Restriction can have one of these set
    • Cell Reserved for operator use – Value can be reserved or not reserved
    • Cell Reservation Extension – Value can be Reserved or Not Reserved
    • Cell Reserved for CSG – Value can be Reserved or Not reserved

Suitable Cell in 3GPP UMTS System

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What is a suitable cell? What are the minimum criteria for 3G suitable cells?

UMTS

A suitable cell in UTRAN system is a cell on which UE can camp on and obtain normal services like voice call and packet call. If UE can not get normal services from the particular cell after camping then it is not considered as a suitable cell.

  • A suitable cell in 3G is part of either
    • the selected PLMN or
    • the registered PLMN or
    • a PLMN of the equivalent PLMN list
  • The cell is not barred as per latest system information
  • The cell is not part of forbidden location area for roaming
  • Cell selection criteria are fulfilled.

If the above criteria is not fulfilled then the cell may be a acceptable cell, barred cell or reserved cell.

Acceptable Cell in UMTS

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What makes a cell acceptable in 3G UMTS system?

UMTS

In acceptable cell UE can camp and make emergency call and receive ETWS notifications if it is supported. An acceptable cell should fulfill the following requirements to make emergency call and receive ETWS primary notifications with or without security support.

  • An 3GPP acceptable cell should not be a barred cell
  • All acceptable cells should fulfill cell reselection criteria

3GPP – What is it?

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What is 3GPP? Why 3GPP Exists?

UMTS

3GPP stands for 3rd generation partnership project. 3GPP combines six telecommunication standardardization groups (ARIB, ATIS, CCSA, ETSI, TTA, TTC) to produce specifications and reports for different 3GPP technologies like 3G (UMTS), HSPA, LTE, LTE Advanced, etc.

3GPP has for technical specification groups. Those are Radio Access Networks (RAN), Service & Systems Aspects (SA), Core Network & Terminals (CT) and GSM EDGE Radio Access Networks (GERAN).

All technical groups meets four to six times every year to discuss and approve new 3GPP features.

The last meeting of the cycle of Plenary meetings is TSG SA, which also has responsibility for the overall coordination of work and for the monitoring of its progress.

World’s biggest mobile phone manufacturers in Q3 2012

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ABI research came out with it’s extensive list of world’s biggest mobile phone manufacturers. Most of the research firms just list the top 5 mobile phone suppliers, but ABI research came out with the extensive list of world’s 11 biggest mobile phone manufactures and the number of handsets they shipped in Q3 2012.

Third quarter 2012 market share by OEM

biggest mobile phone manufacturer Q3 2012

OEM shipments from first quarter 2010 to the third quarter 2012

mobile phone shippments Q3 2012

Overall smartphone shipments vs. non smartphones

Analysis from ABI Research

VendorShipmentsAnalysis
Samsung102.6 millionIn Q3 Samsung extended its handset leadership over Nokia and its smartphone leadership over Apple with over 55 million smartphones shippped. Although shipments of the Galaxy S III started in Q2, shipments of the S III have already reached 30 million and with the Note II coming to market, Samsung is likely to have another record quarter in Q4.
Nokia82.9 millionConsidering the fact that Nokia's Windows Phone 7 devices were made obsolete by the Windows Phone 8 announcement, it is surprising that Nokia was able to muster 6.3 million in smartphone shipments in Q3. On the feature phone side, Nokia's line of Asha handsets continued to find market success for consumers looking for a "smartphone-like" experience.
Apple26.9 millionWhile a slowdown in Q3 shipments was expected, it was assumed that the launch of the iPhone 5 would bring Apple back to it's old 80 percent growth levels. Unfortunately, the initial sales of the iPhone 5 were a little muted due to the limited number of lauch countries in Q3. ABI Research believes that even with a blockbuster quarter of 50 million iPhones in Q4, Apple will not be able to reach the growth rates of its past.
ZTE17.6 million Even with a slight dip in shipments, ZTE was able to capture the fourth position in Q3 after breaking into the top five for the first time last quarter. Having risen from the realm of low-cost handsets and low-end smartphones, ZTE's structure is well adapted to winning market share in an enviroment of shrinking ASP's and margins. ABI Research believes that ZTE's brand strength in its home market of China, will go a long way to keeping ZTE at the top of the list of global handset OEMs. The effects of the recent U.S. reports of ZTE and Huawei being a security threat have yet to manifest, but ABI Research believes this will have more political implications than business implications.
LG14.4 millionLG Shipments increased 10 percent sequentially and the company reagained its profitable status once again. LG will continue its strategy of focusing on LTE smartphones going forward, particularly as this strategy is begining to deliver a profitable quarter here and there. ABI Research believes that winning in this space will be difficult for LG in markets outside of South Korea as Samsung continues to take over every market it touches.
Huawei12.1 millionHistorically considered a low-cost Chinese handset OEM, Huawei shares the international stage with ZTE and TCL/Alcatel, as a rising star from China. Despite being named a potential security threat in the U.S., the "double secret probation" status did not keep Huawei from growing its shipments in Q3.
TCL (Alcatel)10.5 millionTCL was able to show a 11.8 percent year-over-year growth in a quarter where most OEMs were citing competitive and macro economic excuses for their limited growth. Furhtermore TCL delivered 2 million smartphone shipments in Q3 which represents a 1,200+ percent growth year-over-year. TCL has also been able to grow its feature phone shipments and is actively gaining in the Chinese market. ABI Research believes that TCL is yet another Chinese dragon with the teeth to win at home and abroad, and will soon pass Huawei in terms of handset shipments.
Sony Mobile8.8 millionAnd just like that Sony is crawling its way back up the list of top ten OEMs. While Sony did drop out of the top ten last quarter, ABI Research expects that Sony can hold its own in the top ten, although it will likely come from a drop in shipments of its competition more than Sony's expected growth. Much like the Motorola acquisition, Sony has yet to put it's stamp on the devices that are currently in the market, but if it is done properly, Sony can offer Sony Mobile a treasure trove of technology, ecosystem and content support.
Blackberry (RIM)7.4 millionQ3 was a another holding pattern quarter for RIM and its position has risen to No. 9 on the list. On the bright side, RIM did out perform Nokia, Motorola and HTC in terms of smartphone shipments. ABI Research believes that BlackBerry 10 could be a competitive platform, but may arrive too late for RIM to remain in the top ten list. ABI Research believes that finding a company to buy or license BB10 will be very difficult considering that the competitors that need a new OS still can't afford one, and those that can afford one, don't need it.
Motorola7.3 millionWith the acquisition complete and Motorola showing on the financial statements of Google, there is still a lot of speculation as to how Google will manage its $12 billion dollar baby. With the latest portfolio of 3 device types and one extra device featuring an Intel based application processor, it appears that Google wants its Motorola phones to have great battery life, great screens, and minimal marketing.
HTC7.1 million With shipments continuing to drop, HTC may not be on the top 11 or even the top 12 in Q4. HTC has offered guidance that sales in Q4 will be even lower than Q3. Considering that Q4 is a very important quarter, HTC's inability to grow shipments during the holiday season is very troubling indeed.

Market share of different mobile phone manufactures

Samsung25.9%
Nokia21.0%
Apple6.8%
ZTE4.4%
LG3.6%
Huawei3.1%
TCL (Alcatel)2.7%
Sony Mobile2.2%
Blackberry (RIM)1.9%
Motorola1.8%
HTC1.8%
Other24.8%

3GPP LTE CS Fallback (CSFB )

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This tutorial describe details of LTE CSBF : Circuit Switch Fall Back, which is essential for early adaptation of LTE network.

LTE was made for packet based services. But a majority part of today’s traffic originates from CS based services like Voice and SMS. Therefore 3GPP agreed to include an intermediate solution for CS (Circuit Switch) based services until IP-based services like VoLTE completely developed and deployed. Using CSFB (CS Fallback) UE can switch to GERAN, UTRAN or CDMA2000 systems for voice services. CS fall back services are available in those areas where EUTRA systems overlap with GERAN, UTRAN or CDMA2000.

LTE CS Fallback Architecture

For CS Fallback Gs interface between MSC server and MME is required. ia SGs interface, the UE executes combined EPC and IMSI attachment and detachment procedure. Also for MT CS fallback service, CS paging is delivered via SGs interface to MME and ultimately to the UE. The SGs interface is based on the Gs interface.

LTE CS Fallback Architecture

Though CS Fallback is a temporary solution till IMS based VoLTE is completely developed and deployed, but still CS Fallback is important for enabling an easy transition to 4G LTE

There are various solutions suggested for CS Fallback staring from Cell Change Order to target system, RRC Connections Release with redirection and RRC Connection release without redirection.

Listed here are various solutions suggested in different release

LTE CS fallback options in Release 8 and 9

  • Target system Solutions Release UTRAN RRC Connection Release with Redirection without Sys Info Release 8
  • RRC Connection Release with Redirection with Sys Info Release 9
  • PS handover with DRB(s) Release 8
  • GSM RRC Connection Release with Redirection without Sys Info Release 8
  • RRC Connection Release with Redirection with Sys Info Release 9
  • Cell change order without NACC Release 8
  • Cell change order with NACC Release 8
  • PS handover Release 8
  • cdma2000 (1xRTT) RRC Connection Release with Redirection Release 8
  • enhanced 1xCSFB Release 9
  • enhanced 1xCSFB with concurrent HRPD handover Release 9
  • dual receiver 1xCSFB (RRC Connection Release without Release 9 Redirection)

CS Fallback to UMTS

CS Fallback to UMTS is quite often done with RRC Connection Release with redirection info. In this case RRC Connection release message contains the target UTRAN frequency information. Then the UE moves to the target RAT and searches for an acceptable cell by utilizing the frequency information within the RRC Connection Release. Once target cell is located it starts from IDLE and obtains required system information blocks to access the cell. This solution was recommended in 3GPP Release 8.

CS Fallback to GSM

Like CS fallback to UMTS, RRC Connection Release with redirection information is the least-effort solution for CS fallback to GSM. In this solution, the UE RRC Connection in the LTE system is released and the UE is redirected to the GSM system to set up the CS service like CS fallback to UMTS. In this redirection information, the eNodeB can indicate a target frequency. Then the UE moves to the target RAT and searches for a suitable cell by using the frequency information in the RRC Connection Release. Once the UE finds a suitable cell, it starts from IDLE and acquires the necessary system information blocks to access the cell.

I have written another analysis on LTE Circuit Switched Fallback (CSFB) Performance which provides complete picture of CSFB real world results.

Voice Over LTE – VoLTE is Battery Killer

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Voice Over LTE – VoLTE is the technology which will drive the future of voice call over next generation mobile networks and it will replace legacy circuit switched call technology. But recent studies made by Metrico Wireless give some scary results for mass implementation of VoLTE. The worst part is that VoLTE calls consumes more than twice battery power than traditional CS calls.

Every year smartphone battery is getting bigger and bigger. Some of the latest smartphones have the most powerful battery compared to last generation smartphones and it’s increasing at a rate of 14% per year. But still these larger batteries are not enough. The average device now has a dual-core processor, as many as five radios, a high-resolution display, one or more HD cameras, and multi-tasking apps, providing sophisticated new functions for subscribers—while increasing battery drain.

Metrico Wireless conducted studies in two different US cities comparing power consumption due to VoLTE on LTE network and they compared the results with same carrier’s CDMA network. Though Metrico Wireless did not mention the name of the operator, it is easy to guess as there is only one operator supports VoLTE in US.

MetroPCS is the only U.S. operator with a live VoLTE service and a commercially available handset. The 1540 milliamp hour (mAh)-battery on Metro’s sole VoLTE handset, the LG Connect 4G, also lines up with the battery capacity of the device Spirent tested.

The test was conducted for 10 minutes and average power consumption od 10 minute CS call over CDMA was 680 milliwatts (mW) and in the same time 10 minutes VoLTE call over LTE network consumed 1358 mW. Spirent estimated that on a full charge, its test smartphone could support 502.6 minutes of talk time using CDMA only, but the same charge would only deliver 251.8 minutes of talk time using VoIP on the 4G network. And that’s with all other data communications turned off.

Volte Battery Test (LTE vs CDMA)

If this proves to be typical for VoLTE handsets, it will be a big problem. The battery life of the first generation of LTE smartphones was atrocious, and handset vendors have tried to address the problem by slapping fat 3000+ mAh power cells onto their phones. Some carriers are already reluctant to embrace VoLTE since they can still squeeze plenty of life out of their 2G and 3G voice services. If VoLTE proves to be a battery killer, they will be even less inclined to move mobile voice into the IP age.

There are some good news about VoLTE though. Metrico Wireless found that for Multi-RAB scenarios when both Data and VoLTE are active at the same time, LTE performed better than CDMA but with a small margin.

VoLTE Battery Performance MultiRAB

The conclusion is that a lot need to be improved in VoLTE in terms of power consumption.