Proximity Indication - New RRC Uplink Message in Rel-9

The inbound handover from a Macro eNB to an HeNB (a.k.a. Femtocell) is not supported in Release 8. Before making a handover decision to a HeNB, the Macro eNB needs to acquire UE measurement information related to the so-called target CSG cell. Nevertheless, UEs cannot continuously make measurements and read the system information of lots of CSG cells in cases of large scale HeNB deployments.

In order to allow the UE to make those measurements efficiently, a newly defined proximity report can be configured within the RRC Reconfiguration message. This proximity report will allow the UE to send a so-called “proximity indication” to the source eNB in the uplink whenever it is entering or leaving the proximity of one or more cells with CSG IDs that the UEs has in its CSG Whitelist.

A UE that is able to determine that it is near its CSG cell can thus inform the network to take the necessary actions for handover preparation. The detection of proximity is based on an autonomous search function.

The source eNB, upon receiving the proximity indication, might ask the UE to perform measurements of the CSG cell, to read the System Information (SI) or, in case it already has all required information, it might already start the handover procedure. PCI (Physical Cell Identification) confusion is resolved in Release 9. The eNB will ask the UE to report the global cell identity. As usual the UE reporting is using the RRC measurement procedures. The ovell procedure is illustrated in Figure below.

In summary five basic steps can be identified:

1. Proximity configuration/reporting

2. HO measurement configuration/reporting

3. Resolution of PCI confusion by requesting and reporting System Information

4. Access Control in the network

5. HO execution

Since the CSG search can be very slow there are no strict requirements on the inbound handover performance, which can range from one to several 10’s of seconds.

Since the proximity information is based on UE signaling, the network might be receiving a lot of proximity indications, increasing the network load. Therefore, it was agreed to limit proximity indications a UE can send within a certain time frame. A timer, called the prohibit proximity timer, was introduced.

Source:

• 3GPP TS 36.331 v9.3.0 section 5.3.14
• Nomor Research Whitepaper - LTE Home Node Bs and its enhancements in Release 9

7 transmission modes in LTE Rel-8

In Brief:

In Detail:

The Seven Modes of MIMO in LTE

View more documents from All About 4G.

Single Radio Voice Call Continuity (SR‐VCC)

From a 3GPP presentation by Hannu Hietalahti

1. SR-VCC use case

1a. IMS call initiated in LTE can continue in CS domain after moving outside of LTE coverage area

1b. SR-VCC is invoked if no other VoIP capable PS system (e.g., HSPA/eHRPD) is available for VoIP PS-PS HO (Handovers)

1c. Only HO of a single voice bearer from PS to CS is specified

1d. Requires overlapping with 1xRTT/GSM/WCDMA coverage

2. SR-VCC allows a voice calls are anchored in IMS

2a. One-way HO from PS to CS systems (LTE to GSM/UMTS or LTE to 1xRTT)

2b. No simultaneous operation of different radio transceivers needed

3. Rel-9 SR-VCC improvements

3a. IMS support of mid call services (e.g., HOLD, MPTY)

3b. SR-VCC support for emergency calls

4. Video calls, reverse direction from CS call to IMS and optimisations are being studied in Rel-10

LTE CS Fallback Procedure

From a 3GPP presentation by Hannu Hietalahti:

1. CS FallBack from EPS to CS domain

2. CSFB reuses voice and other CS-domain services provided by legacy CS infrastructure

3. EPS redirects the UE to CS Domain for CS services

3a. SMS can be delivered to the UE without redirecting to CS Domain

3b. After CS service the UE returns to LTE, depending on coverage and policy

4. User can decide, based on CLI, whether to accept CSFB request

5. Application of CSFB:

5a. CS capable device camping on LTE cell can establish/receive CS services

5b. Reuse of existing CS infrastructure for voice service until IMS VoIP is deployed

5c. Provide voice roaming support with LTE

5d. Support E911 using existing CS infrastructure

5e. Rel-9 IMS provides full emergency call support

5f. Requires overlapping CS domain coverage

Note: CSFB applies between LTE and GSM, WCDMA and 1xRTT

LTE CS and PS voice service capabilities and architecture

From a 3GPP presentation by Hannu Hietalahti:

Emergency Calls in LTE/SAE Release-9

From a 3GPP presentation by Hannu Hietalahti:

Emergency calls in LTE

Regulatory requirement of emergency calls is supported in Rel-9 for LTE:

1. Detection of emergency numbers in UE

2. Indication and prioritisation of emergency calls

3. Location services, both for routing and user location data for PSAP (Public Safety Answering Point)

4. Callback is possible, but processed as normal call without exceptions

UE matches digits dialledby the user with list of known emergency numbers

1. Emergency number list in the UE is common for CS and PS domain use

2. Default 112 and 911, USIM pre-configuration, downloaded in MM procedure

3. In case of match, the UE shall initiate the call as an emergency call

In IMS emergency calls the UE translates dialled number into emergency service URN

1. Service URN with a top-level service type of "sos" as specified in RFC5031

2. Additionally, sub-service type can be added to indicate emergency category if information on the type of emergency service is known (fire, ambulance, police,…)

P-CSCF (Proxy - Call Session Control Function) must also be prepared to detect emergency call if the UE is not aware of local emergency call

1. This is backup for those cases when the (roaming) UE does not have full information of all local emergency call numbers and initiates a normal call

2. From EPC perspective, it will be a normal PDN connection

Benefit of location information

1. P-CSCF discovers the regionally correct PSAP to take the emergency call

2. PSAP gets information on the precise user location

Related Posts:

• 3GPP Release-9 Features updated
• Service Specific Access Control (SSAC) in 3GPP Release 9
• Public Warning System (PWS) in Release-9
• Europe makes 'eCall' high priority
• 3GPP Earthquake and Tsunami Warning service (ETWS)

'Wi-Fi Direct': New Standard and competition to Femtocells and Bluetooth

Last month when I blogged about WiFi as 4G, i got mixed reactions. Some suggesting that WiFi is just a filler till Femtocells become prevalent and others suggested that in future all devices would with 3G/HSPA/LTE/4G enabled so there may be no need for WiFi.

Well, yesterday I read about the new Wi-Fi Direct (formerly known as 'Wi-Fi Peer-to-Peer') standard that is supposed to make WiFi devices easier to operate with other WiFi devices. I havent explored the security options but I am sure they are well thought out.

Before we go further, you may want to check out the WiFi Direct official video below:

There is an interesting piece in PC World that compares Bluetooth 4.0 with Wi-Fi Direct. I am sure soon both these camps would be listing the merit of their standards and dissing the other one. According to the Register, Bluetooth never really took off in the US. They think Wi-Fi has bigger clout and this would translate to WiFi Direct success.

WiFi Alliance has a recently revised FAQ on Wi-Fi Direct here. Very interesting read. A Media presentation is embedded below and can be downloaded from Slideshare here.

'Wi-Fi Direct' Media Presentation

View more presentations from Zahid Ghadialy.

The devices have already started undergoing certification and commercial devices should be available by the end of this year.

Finally, while there is a lot of debate going on about WiFi v/s Femtocells and I respect everyone's views and arguments on this debate, I think Wi-Fi direct may give a kicking to the Femtocell manufacturers where it hurts the most.

One of the strong arguments in the favour of Femtocell is the seamless roaming. With Wi-Fi direct you may be able to seamlessly connect to various Wi-Fi devices and Access points. This certainly counts big time in their favour.

Certainly the gate is still wide open for some Femtocell based killer apps which would turn the tide in their favour but for now I am looking forward to some Wi-Fi direct devices.

Understanding smartphone traffic - Interesting Presentation

Understanding smartphone traffic - Droidcon

View more presentations from Ericsson Labs

If you like the above then also check out the Fast Dormancy in Release-8.

ETSI M2M Workshop summary and conclusions

As I mentioned earlier about the M2M workshop held in Paris, the following are the highlights from press release after the event:

ETSI's first Open Machine-to-Machine Workshop broke all records for attendance, laying out the next steps for achieving M2M applications worldwide, and confirming a leading role for the standards organisation.

'Machine-to-Machine (M2M) communications need standards – and ETSI is taking the lead to make sure that the standards are in place.' This was the main conclusion from ETSI's M2M workshop which took place on 19 and 20 October. With over 220 attendees from across the world, this was the most popular ETSI workshop to date, with the high degree of interest reflecting the enormous potential that is foreseen for M2M applications and technologies.

Participants heard how existing and evolving communication technologies networks (mostly wireless (cellular and low-power), but also fixed networks, including power line communications) provide a firm basis for connecting M2M sensors and applications. Specification of appropriate interfaces that allow network technology neutrality is a priority, and one that ETSI is already addressing.

The workshop included two live demonstrations organised by InterDigital Inc. These demonstrated an M2M gateway and core network, and an M2M Wireless Personal Area Network (sensors connecting via low-power wireless devices to a database, simulating e-Health, home automation and security application scenarios). The implementations were based on current specifications from ETSI's M2M Technical Committee and confirmed both the effectiveness of the implications and of the ETSI specifications. In addition, poster sessions presented the work of six research and development projects related to M2M and the Future Internet, part of the European Commission's 7th Framework Programme (FP7).

The standards work of ETSI's M2M Technical Committee is reaching an advanced stage, and many network operators are encouraging a first release of M2M standards by early 2011. The committee is currently finalising the architecture for the service platform that will enable the integration of multiple vertical M2M applications. The workshop confirmed that ETSI is well placed to address a vital aspect of standardisation in support of M2M – the specification of interfaces that will facilitate the interconnection and interoperability of the diverse applications and of the networks that will underlie them.

Marylin Arndt of France Telecom, Chairman of ETSI's M2M Technical Committee, said: 'The committee will continue in its role of creating standards that build on what we already have, to ensure that the emerging 'vertical' M2M applications can be supported effectively. At the same time, the committee (and ETSI in general) has a vital responsibility to co-ordinate and direct the wider work on M2M. We are here to lead the way.'

All presentations could be downloaded from here.

The conclusions from the meeting is summarised in the presentation embedded below:

ETSI M2M Workshop Oct. 2010 Conclusions

View more presentations from Zahid Ghadialy

Complete Coverage of 4G World 2010 ... in case you missed

Wireless Week has a very good magazine with detailed highlights of everything that happened in the recently concluded 4G World event in Chicago. The links are as follows:

Day 1

Day 2

Day 3