Showing posts with label Release 9. Show all posts
Showing posts with label Release 9. Show all posts

Wednesday 15 December 2010

SON in Heterogeneous Networks

Another presentation from the SON 2010 Conference based on yesterdays theme of HetNets.


Presented by Seungpyo Hong of Institute of Network Technology, SK Telecom.

Wednesday 8 December 2010

SON for reducing Opex in Legacy Networks

Presented by Stéphane Téral, Principal Analyst, Mobile and FMC Infrastructure, Infonetics Research in the 1st Self-Organizing Networks Conference, 30th Nov and 1st Dec. 2010 at the Waldorf Hilton.

Tuesday 7 December 2010

SON framework in 3GPP

From a Presentation by Cinzia Sartori from Nokia Siemens Networks (NSN) in the Self-Organising Networks Conference in London, Nov. 2010

Release 8 functionality
• Self-configuration procedures

Release 9 enhancements
• Self-optimization procedures
• Energy Saving Intra-RAT

Release 10 objectives
• Extend Self-optimization procedures , including inter-RAT
• Minimization of Drive Test (MDT)
• Energy Saving extension, including Multi-RAT (Study Item)
• 3G-ANR
• SON Conflict Resolution

SON features for R11 (Probably - Under Discussion)
• Minimization of Drive Tests (MDT) enhancements
• Mobility Robustness Optimization for MultiRAT
• SON for LTE-A features defined in Rel.10
•• Hetrogeneous Networks aka. HetNet?
•• SON for Relays
•• SON for Carrier Aggregation

Thursday 11 November 2010

UEInformationRequest/UEInformationResponse - New RRC messages in Release-9

As is obvious from the title, The UE information procedure is used by E-UTRAN to request the UE to report information [1].

There are two different scenarios for the Network to send the UEInformationRequest message to the UE. One is to find out the number of RACH preambles it needed for the random access procedure and the other is to get the measurement information when a Radio Link Failure (RLF) occurred.

[2] also provides the following detail:

The network may poll for the UE report after a successful random access procedure (UEInformationRequest) and the UE responds with the number of preambles sent by MAC for the last successfully completed random access procedure and whether contention is detected by MAC for at least one of the transmitted preambles for the last successfully completed random access procedure (UEInformationResponse).

Source:

[1] 3GPP TS 36.331 V9.3.0: Radio Resource Control (RRC); Protocol specification - Section 5.6.5

[2] 3GPP TR 36.902 V9.2.0: Self-configuring and self-optimizing network (SON) use cases and solutions

Wednesday 10 November 2010

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:

Monday 8 November 2010

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

Thursday 4 November 2010

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:

Tuesday 19 October 2010

LTE Self Optimizing Networks (SON) enhancements for Release-10

Capacity and Coverage Optimisation (CCO) was already nominally part of the Release-9 WI, but could not be completed due to amount of work related to other use cases.

Energy Savings are a very important topic, especially for operators, as solutions derived for this use case can significantly limit their expenses. According to TR 36.902 this solution should concern switching off cells or whole base stations. This may require additional standardised methods, once there is need identified for.

Basic functionality of Mobility Load Balancing (MLB) and Mobility Robustness Optimisation (MRO), also listed in TR 36.902, were defined in Rel.9. However, successful roll-out of the LTE network requires analysing possible enhancements to the Rel.9 solutions for MLB and MRO. In particular, enhancements that address inter-RAT scenarios and inter-RAT information exchange must be considered. These enhancements should be addressed in Rel.10.

There may also be other use cases for LTE for which SON functionality would bring optimisations.

Although, it is of primary interest to provide coverage to users during a roll-out, it is equally important to enhance the capacity of the network during operation. As such, both coverage and capacity are considered in the use case and supported by the SON function. The CCO SON function should be configured through appropriate objectives and targets in order to meet the operator’s requirement on coverage and capacity, and the prioritization between them.

The following use cases and scenarios are planned for Release-10:

Coverage and Capacity Optimisation (CCO)
The use case is to enable detection of following problems:
Priority 1: coverage problems, e.g. coverage holes
Priority 2: capacity problems

Mobility Robustness Optimisation (MRO) enhancements
The use case is to enable detection and to provide tools for possible correction of following problems:
Connection failures in inter-RAT environment:
o Priority 1: at HOs from LTE to UMTS/GSM
o Priority 2: at HOs from UMTS/GSM to LTE
Obtaining UE measurements in case of unsuccessful re-establishment after connection
failure
Ping-pongs in idle mode (inter-RAT and intra-LTE environment)
Ping-pongs in active mode (inter-RAT)
HO to wrong cell (in intra-LTE environment) that does not cause connection failure (e.g. short stay problem)

Mobility Load Balancing (MLB) enhancements
The use case is to fulfil following objectives:
Improving reliability of MLB in intra-LTE scenarios
Improving functionality of the MLB in inter-RAT scenarios (the transport method agreed for R9 should be used for R10).

For more info see 3GPP TS 32.521: Self-Organizing Networks (SON) Policy Network Resource Model (NRM) Integration Reference Point (IRP); Requirements; Release-10

There is also a Self-Organising Networks Conference that I am attending next month and I plan to give SON lots of coverage before and after the event.

If you havent read the 3G Americas whitepaper on SON, it is definitely worth a read. I have embedded it below.



Tuesday 1 June 2010

LTE Femtocell Enhancements for Release-9

LTE Release 9 provides further functionality to support more efficiently HeNBs operation and to provide a better user experience. The key functionality added the Radio Access Network for HeNBs in Release 9 are:

• A novel Hybrid Cell concept
• Management of out-of-date CSG info
• Inbound Mobility (including proximity reports)
• Access Control
• Operation, Administration and Maintenance for HeNB
• Operator controlled CSG list
• RF Requirements for TDD and FDD HeNBs

Nomor Research have recently released a paper that covers all these issues and much more. Titled "LTE Home Node Bs and its enhancements in Release 9", its available to download here.

Friday 26 March 2010

E-UTRAN Mobility Drivers and Limitations

Many years back, when things used to be simple, I wrote a tutorial about Handovers in UMTS. It would be very difficult to write a similarly simple tutorial for LTE. Things are a bit complicated because there are many different conditions in which handovers can take place.

It was also easier to visualise the Intra-frequency and Inter-frequency handovers in UMTS and you can probably do the same to some extent in LTE but with things getting more complicated and carrier aggregation, classifying handovers in these categories may be difficult.

3GPP TS 36.300 has an informative Annex E which details the scenarios in which handovers and cell change can/will take place.

It is best to go and see Annex E in detail. Here is a bit of summary from there:

Intra-frequency mobility: intra-frequency mobility is the most fundamental, indispensable, and frequent scenario. With the frequency reuse being one in E-UTRAN, applying any driver other than the “best radio condition” to intra-frequency mobility control incur increased interference and hence degraded performance.

Inter-frequency mobility: as in UTRAN, an operator may have multiple carriers/bands for E-UTRAN working in parallel. The use of these frequency layers may be diverse. For example, some of these frequency layers may utilise the same eNB sites and antenna locations (i.e., co-located configuration), whereas some may be used to form a hierarchical cell structure (HCS), or even be used for private networks. Some frequency layers may provide MBMS services, while some may not. Moreover, E-UTRAN carriers/bands may be extended in the future to increase capacity.

Inter-RAT mobility: the aspects that need to be considered for inter-RAT are similar to those for inter-frequency. For mobility solutions to be complete with the inter-RAT drivers, relevant updates would be necessary on the legacy (UTRAN/GERAN) specifications. This will add to the limitations, which are evidently more effective in inter-RAT.


The drivers for mobility control are:

Best radio condition: The primary purpose of cell reselection, regardless of intra-frequency, inter-frequency, or inter-RAT, is to ensure that the UE camps on/connects to the best cell in terms of radio condition, e.g., path loss, received reference symbol power, or received reference symbol Es/I0. The UE should support measurements to suffice this aspect.

Camp load balancing: This is to distribute idle state UEs among the available bands/carriers/RATs, such that upon activation, the traffic loading of the bands/carriers/RATs would be balanced. At least the path loss difference between different bands should be compensated to avoid UEs concentrating to a certain frequency layer.

Traffic load balancing: This is to balance the loading of active state UEs, using redirection for example. In E-UTRAN, traffic load balancing is essential because of the shared channel nature. That is, the user throughput decreases as the number of active UEs in the cell increases, and the loading directly impacts on the user perception.

UE capability: As E-UTRAN bands/carriers may be extended in the future, UEs having different band capabilities may coexist within a network. It is also likely that roaming UEs have different band capabilities. Overlaying different RATs adds to this variety.

Hierarchical cell structures: As in UTRAN, hierarchical cell structures (HCS) may be utilised in E-UTRAN to cover for example, indoors and hot spots efficiently. It is possible that E-UTRAN is initially deployed only at hot spots, in which case this driver becomes essential for inter-RAT, not just for inter-frequency. Another use case would be to deploy a large umbrella cell to cover a vast area without having to deploy a number of regular cells, while providing capacity by the regular cells on another frequency.

Network sharing: At the edge of a shared portion of a network, it will be necessary to direct UEs belonging to different PLMNs to different target cells.

Private networks/home cells: Cells that are part of a sub-network should prioritise the camping on that sub-network. UEs that do not belong to private sub-networks should not attempt to camp or access them.

Subscription based mobility control: This mobility driver aims to limit the inter-RAT mobility for certain UEs, e.g., based on subscription or other operator policies.

Service based mobility control: An operator may have different policies in allocating frequencies to certain services. For example, the operator may concentrate VoIP UEs to a certain frequency layer or RAT (e.g., UTRAN or GERAN), if evaluations prove this effective. UEs requiring higher data rates may better be served on a frequency layer or RAT (e.g., E-UTRAN) having a larger bandwidth. The operator may also want to accommodate premium services on a certain frequency layer or RAT, that has better coverage or larger bandwidth.

MBMS: For Release-9, no new mobility procedures compared to Release-8 are included specifically for MBMS. In future releases the following should be considered. As MBMS services may be provided only in certain frequency layers, it may be beneficial/necessary to control inter-frequency/RAT mobility depending on whether the UE receives a particular MBMS service or not. For MBMS scenarios only, UE based service dependent cell reselection might be considered acceptable. This aspect also depends on the UE capability for simultaneous reception of MBMS and unicast.


While the issues mentioned above drive E-UTRAN towards “aggressive” mobility control, the limiting factors also have to be considered:

UE battery saving: The mobility solution should not consume excessive UE battery, e.g., due to measurements, measurement reporting, broadcast signalling reception, or TA update signalling.
Network signalling/processing load: The mobility solution should not cause excessive network signalling/processing load. This includes over-the-air signalling, S1/X2 signalling, and processing load at network nodes. Unnecessary handovers and cell reselections should be avoided, and PCH and broadcast signalling, as well as dedicated signallings, should be limited.

U-plane interruption and data loss: U-plane interruption and data loss caused by the mobility solution should be limited.

OAM complexity: The mobility solution should not demand excessive efforts in operating/maintaining a network. For example, when a new eNB is added or an existing eNB fails, the mobility solution should not incur excessive efforts to set up or modify the parameters.

More details available in Annex E of 3GPP TS 36.300

Wednesday 3 March 2010

Commercial Mobile Alert System (CMAS) in Release-9

I have blogged about Public Warning System and covered CMAS as part of that earlier.

The following is an extract from 3G Americas white paper, "3GPP Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond: HSPA+, SAE/LTE and LTE-Advanced,":

In response to the Warning, Alert, and Response Network (WARN) Act passed by Congress in 2006, the Federal Communications Commission (FCC) established the Commercial Mobile Alert Service (CMAS) to allow wireless service providers who choose to participate, to send emergency alerts as text messages to their users who have CMAS capable handsets.

The FCC established a Commercial Mobile Service Alert Advisory Committee (CMSAAC) for the development of a set of recommendations for the support of CMAS. The CMSAAC recommendations were included as the CMAS Architecture and Requirements document in the FCC Notice of Proposed Rule Making (NPRM) which was issued in December 2007. In 2008, the FCC issued three separate Report and Order documents detailing rules (47 Code of Federal Regulations [CFR] Part 10) for CMAS. The FCC CMAS First Report and Order specifies the rules and architecture for CMAS. The FCC CMAS Second Report and Order establishes CMAS testing requirements and describes the optional capability for Noncommercial Educational (NCE) and public broadcast television stations distribute geo-targeted CMAS alerts. The FCC CMAS Third Report and Order defined the CMAS timeline, subscriber notification requirements for CMSPs, procedures for CMSP participation elections and the rules for subscriber opt-out. The FCC also issued a CMAS Reconsideration and Erratum document.

The CMAS network will allow the
Federal Emergency Management Agency (FEMA), to accept and aggregate alerts from the President of the United States, the National Weather Service (NWS), and state and local emergency operations centers, and then send the alerts over a secure interface to participating commercial mobile service providers (CMSPs). These participating CMSPs will then distribute the alerts to their users. between the issuance of the second and third Report & Order documents.

As defined in the FCC CMAS Third Report and Order, CMSPs that voluntarily choose to participate in CMAS must begin an 18 month period of development, testing and deployment of the CMAS no later than 10 months from the date that the Government Interface Design specifications available. On December 7, 2009, the CMAS timeline of the FCC CMAS Third Report and Order was initiated
with the announcement by FEMA and the FCC that the Joint ATIS/TIA CMAS Federal Alert GW to CMSP GW Interface Specification (J-STD-101) has been adopted as the Government Interface Design specification referenced in the FCC CMAS Third Report and Order.

Participating CMSPs must be able to target alerts to individual counties and ensure that alerts reach customers roaming outside a provider’s service area. Participating CMSPs must also transmit alerts with a dedicated vibration cadence and audio attention signal. Emergency alerts will not interrupt calls in progress. CMAS supports only English text-based alert messages with a maximum displayable message size of 90 English characters.


For purposes of CMAS, emergency alerts will be classified in one of three categories:

1. Presidential Alerts. Any alert message issued by the President for local, regional, or national emergencies and are the highest priority CMAS alert

2. Imminent Threat Alerts. Notification of emergency conditions, such as hurricanes or tornadoes, where there is an imminent threat to life or property and some immediate responsive action should be taken

3. Child Abduction Emergency/AMBER Alerts. Alerts related to missing or endangered children due to an abduction or runaway situation

The subscribers of participating CMSPs may opt out of receiving Imminent Threat and Child Abduction/AMBER alerts, but cannot opt out from Presidential Alerts.

The following figure shows the CMAS Reference Architecture as defined in the FCC CMAS First Report and Order:


Reference Point C is the secure interface between the Federal Alert GW and the Commercial Mobile Service Provider (CMSP) GW. The Reference Point C interface supports delivery of new, updated or canceled wireless alert messages, and supports periodic testing of the interface. This interface is defined in the
J-STD-101, the Joint ATIS/TIA CMAS Federal Alert GW to CMSP GW Interface Specification.

Federal Government entity (i.e. FEMA) responsible for the administration of the Federal Alert GW. FEMA will perform the function of aggregating all state, local, and federal alerts and will provide one logical interface to each CMSP who elects to support CMAS alerts.

For GSM and UMTS systems, wireless alert messages that are received by CMSP GWs will be transmitted to targeted coverage areas using GSM-UMTS Cell Broadcast Service (CBS). The CMAS functionality does not require modifications to the 3GPP-defined Cell Broadcast Service.

The ATIS WTSC-G3GSN Subcommittee is developing the CMAS via GSM-UMTS Cell Broadcast Service Specification. The purpose of this standard is to describe the use of the GSM-UMTS Cell Broadcast Service for the broadcast of CMAS messages. The standard includes the mapping of CMAS application level messages to the Cell Broadcast Service message structure.

The ATIS WTSC-G3GSN Subcommittee is developing the Cell Broadcast Entity (CBE) to Cell Broadcast Center (CBC) Interface Specification. The purpose of this standard is to define a standard XML based interface to the Cell Broadcast Center (CBC). The CMSP Alert GW will utilize this interface to provide the CMAS Alert message information to the CBC for broadcast via CBS.

The ATIS WTSC-G3GSN Subcommittee has developed the Implementation Guidelines and Best Practices for GSM/UMTS Cell Broadcast Service Specification and this specification was approved in October 2009. The purpose of this specification is to describe implementation guidelines and best practices related to GSM/UMTS Cell Broadcast Service regardless of the application using CBS. This specification is not intended to describe an end-to-end Cell Broadcast architecture, but includes clarifications to the existing 3GPP CBS standards as well as “best practices” for implementation of the 3GPP standards. CMAS is an example of an application that uses CBS.

J-STD-100, Joint ATIS/TIA CMAS Mobile Device Behavior Specification, defines the common set of requirements for GSM, UMTS, and CDMA based mobile devices behavior whenever a CMAS alert message is received and processed. A common set of requirements will allow for a consistent user experience regardless of the associated wireless technology of the mobile device. Additionally, this common set of requirements will allow the various local, state, and Federal level government agencies to develop subscriber CMAS educational information that is independent of the wireless technology.

CMAS VIA LTE/EPS

In order to comply with FCC requirements for CMAS, CMSPs have a need for standards development to support CMAS over LTE/EPS as it relates to the network-user interface generally described as the “E-Interface” in the CMAS Reference Architecture. The intent of ATIS WTSC-G3GSN is to build upon LTE text broadcast capabilities currently being specified by 3GPP for the Public Warning System (PWS).

3GPP STANDARDS

3GPP TS 22.268. Public Warning System (PWS) Requirements, covers the core requirements for the PWS and covers additional subsystem requirements for the Earthquake and Tsunami Warning System (ETWS) and for CMAS. TS 22.268 specifies general requirements for the broadcast of Warning Notifications to broadcast to a Notification Area that is based on the geographical information as specified by the Warning Notification Provider. This specification also defines specific CMAS requirements based on the three Reports & Orders issued to date by the FCC.

3GPP TS 23.401. GPRS enhancements for E-UTRAN access, specifies the Warning System Architecture for 3GPP accesses and the reference point between the Cell Broadcast Center (CBC) and Mobility Management Entity (MME) for warning message delivery and control functions. This TS identifies the MME functions for warning message transfer (including selection of appropriate eNodeB), and provides Stage 2 information flows for warning message delivery and warning message cancel. The architecture and warning message delivery and control functions support CMAS.

3GPP TS 29.168. Cell Broadcast Center interfaces with the EPC – Stage 3, specifies the procedures and application protocol between the Cell Broadcast center and the MME for Warning Message Transmission, including the messages, information elements and procedures needed to support CMAS.

3GPP TS 36.300. E-UTRA and E-UTRAN – Overall description – Stage 2, specifies the signaling procedures for the transfer of warning messages from the MME to the eNodeB. The signaling procedures support CMAS operations.

3GPP TS 36.331. E-UTRA Radio Resource Control (RRC) – Protocol specification, specifies the radio resource control protocol for UE-to-E-UTRAN radio interface and describes CMAS notification and warning message transfer.

3GPP TS 36.413. E-UTRAN – S1 Application Protocol (S1AP), specifies the E-UTRAN radio network layer signaling protocol between the MME and eNodeB, and describes the warning message transfer needed for CMAS.

3GPP participants are working to complete these specifications and other UE procedures for supporting PWS and CMAS.

ATIS WTSC-G3GSN will develop a Standard for a CMAS via LTE Broadcast Capability Specification. This Standard will map the CMAS application level messages to the LTE warning message transfer protocol (i.e. for CMAS).

This ATIS WTSC-G3GSN effort has an anticipated completion date of December 31, 2010. This takes into account the time needed for completion of the ongoing 3GPP standards development on warning message broadcast for LTE.

ATIS WTSC G3GSN and TIA TR45.8 Subcommittees in conjunction with FEMA will also be jointly developing a testing certification specification for the Reference Point C interface between the Federal Alert GW and the CMSP GW based upon the requirements defined in J-STD-101. This specification has an anticipated completion date of December 31, 2010.

Tuesday 16 February 2010

Self Organizing Networks and Enhancements

I have blogged about SON earlier here and here. The following is an update from the 3G Americas Whitepaper on Mobile Broadband:

SON concepts are included in the LTE (E-UTRAN) standards starting from the first release of the technology (Rel-8) and expand in scope with subsequent releases. A key goal of 3GPP standardization is the support of SON features in multi-vendor network environments. 3GPP has defined a set of LTE SON use cases and associated SON functions. The standardized SON features effectively track the expected LTE network evolution stages as a function of time. With the first commercial networks expected to launch in 2010, the initial focus of Rel-8 has been functionality associated with initial equipment installation and integration.

The scope of the first release of SON (Rel-8) includes the following 3GPP functions, covering different aspects of the eNodeB self-configuration use case:
• Automatic Inventory
• Automatic Software Download
• Automatic Neighbor Relations
• Automatic PCI Assignment

The next release of SON, as standardized in Rel-9, will provide SON functionality addressing more maturing networks. It includes the following additional use cases:
• Coverage & Capacity Optimization
• Mobility optimization
• RACH optimization
• Load balancing optimization

Other SON-related aspects that are being discussed in the framework of Rel-9 include improvement on the telecom management system to increase energy savings, a new OAM interface to control home eNodeBs, UE reporting functionality to minimize the amount of drive tests, studies on self testing and self-healing functions and minimization of drive testing. It should be clarified that SON-related functionality will continue to expand through the subsequent releases of the LTE standard.

The SON specifications have been built over the existing 3GPP network management architecture, reusing much functionality that existed prior to Rel-8. These management interfaces are being defined in a generic manner to leave room for innovation on different vendor implementations. More information on the SON capabilities in 3GPP can be found in 3G Americas’ December 2009 white paper, The Benefits of SON in LTE.

SON technologies have been introduced in Rel-8/Rel-9 to help decrease the CAPEX and OPEX of the system. LTE-Advanced further enhances the SON with the following features:
  • Coverage and Capacity Optimization. Coverage and Capacity Optimization techniques are currently under study in 3GPP and will provide continuous coverage and optimal capacity of the network. The performance of the network can be obtained via key measurement data and adjustments can then be made to improve the network performance. For instance, call drop rates will give an initial indication of the areas within the network that have insufficient coverage and traffic counters can be used to identify capacity problems. Based on these measurements, the network can optimize the performance by trading off capacity and coverage.
  • Mobility Robustness Optimization. Mobility Robustness Optimization aims at reducing the number of hand over related radio link failures by optimally setting the hand over parameters. A secondary objective is to avoid the ping-pong effect or prolonged connection to a non-optimal cell.
  • Mobility Load Balancing. Related to Mobility Robustness is Mobility Load Balancing, which aims to optimize the cell reselection and handover parameters to deal with unequal traffic loads. The goal of the study is to achieve this while minimizing the number of handovers and redirections needed to achieve the load balancing.
  • RACH Optimization. To improve the access to the system, RACH Optimization has been proposed to optimize the system parameters based upon monitoring the network conditions, such as RACH load and the uplink interference. The goal is to minimize the access delays for all the UEs in the system and the RACH load.

In addition to the enhanced SON technologies described above, minimization of manual drive testing functionality is also currently under examination in 3GPP to enhance and minimize the effort for optimization of the LTE-Advance network. The main goal is to automate the collection of UE measurement data. In so doing, it will minimize the need for operators to rely on manual drive tests to optimize the network. In general, a UE that is experiencing issues, such as lack of coverage, traffic that is unevenly distributed or low user throughput, will automatically feed back measurement data to the network which may be used by the network as a foundation for network optimization.

SON related 3GPP references can be found on Martin Sauter's blog here.

Friday 12 February 2010

A quick Introduction to M2M Communications

Machine-to-Machine (M2M) communications is a healthy sector that' s expanding rapidly and generating significant revenues for mobile network operators (MNOs). Devices outnumber subscribers by an order of magnitude, but the term doesn' t do justice to the concept and the market it represents.

The following is from 3G Americas report on 3GPP standards and their evolution to 4G:

By leveraging connectivity, Machine-to-Machine (M2M) communication would enable machines to communicate directly with one another. In so doing, M2M communication has the potential to radically change the world around us and the way that we interact with machines.

In Rel-10, 3GPP is in the process of establishing requirements for 3GPP network system improvements that support Machine-Type Communications (MTC). The objective of this study is to identify 3GPP network enhancements required to support a large number of MTC devices in the network and to provide necessary network enablers for MTC communication service. Specifically, transport services for MTC as provided by the 3GPP system and the related optimizations are being considered as well as aspects needed to ensure that MTC devices and/or MTC servers and/or MTC applications do not cause network congestion or system overload. It is also important to enable network operators to offer MTC services at a low cost level, to match the expectations of mass market machine-type services and applications.

The 3GPP study on M2M communications has shown potential for M2M services beyond the current "premium M2M market segment." The example of applications for mass M2M services include machine type communications in smart power grid, smart metering, consumer products, health care, and so forth. The current mobile networks are optimally designed for Human-to-Human communications, but are less optimal for M2M applications.


A study item on M2M communications (3GPP TR 22.868) was completed in 2007; however, no subsequent normative specification has been published. For Rel-10 and beyond, 3GPP intends to take the results on network improvements from the study item forward into a specification phase and address the architectural impacts and security aspects to support MTC scenarios and applications. As such, 3GPP has defined a work item on Network Improvements for Machine-Type Communication (NIMTC). The following goals and objectives are described in the work item:

The goal of this work item is to:
• Provide network operators with lower operational costs when offering machine-type communication services
• Reduce the impact and effort of handling large machine-type communication groups
• Optimize network operations to minimize impact on device battery power usage
• Stimulate new machine-type communication applications by enabling operators to offer services tailored to machine-type communication requirements

The objectives of this work item include:
• Identify and specify general requirements for machine-type communications
• Identify service aspects where network improvements (compared to the current H2H oriented services) are needed to cater for the specific nature of machine-type communications
• Specify machine-type communication requirements for these service aspects where network improvements are needed for machine-type communication
• Address system architecture impacts to support machine-type communication scenarios and applications

A RAN study item to investigate the air interface enhancements for the benefit of M2M communication has also been recently approved. The study will be initiated in early 2010.

Further Reading:

Thursday 11 February 2010

UICC and USIM in 3GPP Release 8 and Release 9


In good old days of GSM, SIM was physical card with GSM "application" (GSM 11.11)

In the brave new world of 3G+, UICC is the physical card with basic logical functionality (based on 3GPP TS 31.101) and USIM is 3G application on a UICC (3GPP TS 31.102). The UICC can contain multiple applications like the SIM (for GSM), USIM and ISIM (for IMS). There is an interesting Telenor presentation on current and future of UICC which may be worth the read. See references below.

UICC was originally known as "UMTS IC card". The incorporation of the ETSI UMTS activities into the more global perspective of 3GPP required a change of this name. As a result this was changed to "Universal Integrated Circuit Card". Similarly USIM (UMTS Subscriber Identity Module) changed to Universal Subscriber Identity Module.

The following is from the 3G Americas Whitepaper on Mobile Broadband:

UICC (3GPP TS 31.101) remains the trusted operator anchor in the user domain for LTE/SAE, leading to evolved applications and security on the UICC. With the completion of Rel-8 features, the UICC now plays significant roles within the network.

Some of the Rel-8 achievements from standards (ETSI, 3GPP) are in the following areas:

USIM (TS 31.102)
With Rel-8, all USIM features have been updated to support LTE and new features to better support non-3GPP access systems, mobility management, and emergency situations have been adopted.

The USIM is mandatory for the authentication and secure access to EPC even for non-3GPP access systems. 3GPP has approved some important features in the USIM to enable efficient network selection mechanisms. With the addition of CDMA2000 and HRPD access technologies into the PLMN, the USIM PLMN lists now enable roaming selection among CDMA, UMTS, and LTE access systems.

Taking advantage of its high security, USIM now stores mobility management parameters for SAE/LTE. Critical information like location information or EPS security context is to be stored in USIM rather than the device.

USIM in LTE networks is not just a matter of digital security but also physical safety. The USIM now stores the ICE (In Case of Emergency) user information, which is now standardized. This feature allows first responders (police, firefighters, and emergency medical staff) to retrieve medical information such as blood type, allergies, and emergency contacts, even if the subscriber lies unconscious.

3GPP has also approved the storage of the eCall parameters in USIM. When activated, the eCall system establishes a voice connection with the emergency services and sends critical data including time, location, and vehicle identification, to speed up response times by emergency services. ECalls can be generated manually by vehicle occupants or automatically by in-vehicle sensors.

TOOLKIT FEATURES IMPROVEMENT (TS 31.111)
New toolkit features have been added in Rel-8 for the support of NFC, M2M, OMA-DS, DM and to enhance coverage information.

The contactless interface has now been completely integrated with the UICC to enable NFC use cases where UICC applications proactively trigger contactless interfaces.

Toolkit features have been updated for terminals with limited capabilities (e.g. datacard or M2M wireless modules). These features will be notably beneficial in the M2M market where terminals often lack a screen or a keyboard.

UICC applications will now be able to trigger OMA-DM and DS sessions to enable easier device support and data synchronization operations, as well as interact in DVB networks.

Toolkit features have been enriched to help operators in their network deployments, particularly with LTE. A toolkit event has been added to inform a UICC application of a network rejection, such as a registration attempt failure. This feature will provide important information to operators about network coverage. Additionally, a UICC proactive command now allows the reporting of the signal strength measurement from an LTE base station.

CONTACT MANAGER
Rel-8 defined a multimedia phone book (3GPP TS 31.220) for the USIM based on OMA-DS and its corresponding JavaCard API (3GPP TS 31.221).

REMOTE MANAGEMENT EVOLUTION (TS 31.115 AND TS 31.116)
With IP sessions becoming prominent, an additional capability to multiplex the remote application and file management over a single CAT_TP link in a BIP session has been completed. Remote sessions to update the UICC now benefit from additional flexibility and security with the latest addition of the AES algorithm rather than a simple DES algorithm.

CONFIDENTIAL APPLICATION MANAGEMENT IN UICC FOR THIRD PARTIES
The security model in the UICC has been improved to allow the hosting of confidential (e.g. third party) applications. This enhancement was necessary to support new business models arising in the marketplace, with third party MVNOs, M-Payment and Mobile TV applications. These new features notably enable UICC memory rental, remote secure management of this memory and its content by the third party vendor, and support new business models supported by the Trusted Service Manager concept.

SECURE CHANNEL BETWEEN THE UICC AND TERMINAL
A secure channel solution has been specified that enables a trusted and secure communication between the UICC and the terminal. The secure channel is also available between two applications residing respectively on the UICC and on the terminal. The secure channel is applicable to both ISO and USB interfaces.

RELEASE 9 ENHANCEMENTS: UICC: ENABLING M2M AND FEMTOCELLS
The role of femtocell USIM is increasing in provisioning information for Home eNodeB, the 3GPP name for femtocell. USIMs inside handsets provide a simple and automatic access to femtocells based on operator and user-controlled Closed Subscriber Group list.

Work is ongoing in 3GPP for the discovery of surrounding femtocells using toolkit commands. Contrarily to macro base stations deployed by network operators, a femtocell location is out of the control of the operator since a subscriber can purchase a Home eNodeB and plug it anywhere at any time. A solution based on USIM toolkit feature will allow the operator to identify the femtocells serving a given subscriber. Operators will be able to adapt their services based on the femtocells available.

The upcoming releases will develop and capitalize on the IP layer for UICC remote application management (RAM) over HTTP or HTTPS. The network can also send a push message to UICC to initiate a communication using TCP protocol.

Additional guidance is also expected from the future releases with regards to the M2M dedicated form factor for the UICC that is currently under discussion to accommodate environments with temperature or mechanical constraints surpassing those currently specified by the 3GPP standard.

Some work is also expected to complete the picture of a full IP UICC integrated in IP-enabled terminal with the migration of services over EEM/USB and the capability for the UICC to register on multicast based services (such as mobile TV).

Further Reading:

Monday 8 February 2010

3G Americas Publishes New Report on Technology choices for Mobile Broadband

3G Americas, a wireless industry trade association representing the GSM family of technologies including LTE, announced that it has published its highly anticipated resource report on 3rd Generation Partnership Project (3GPP) standards and their evolution to IMT-Advanced, or 4G. The white paper, 3GPP Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond: HSPA+, SAE/LTE and LTE-Advanced, provides in-depth examination of 3GPP technology standards from a technical, business and applications standpoint.

“The 3GPP technology standards deliver mobile connectivity to more than 4 billion users worldwide today and have been developed to continue evolving to higher levels of performance with mobile broadband innovation,” said Chris Pearson, president of 3G Americas. “GSM operators can choose to evolve their networks in ways that best suit their assets and business environments with benefits that offer flexibility, scalability and economic advantages, whether they choose HSPA+ or LTE.”



UMTS-HSPA is the world’s leading 3G technology and is the preferred choice for the majority of wireless operators and subscribers today and into the future. The global demand for wireless data services continues to drive the rapid growth of HSPA technology with 303 commercial HSPA networks and over 454 million UMTS-HSPA subscriptions reported at the end of 2009 by Informa Telecoms & Media. Informa has further projected that by year-end 2012, worldwide subscriptions to UMTS-HSPA will reach nearly 1.4 billion; by year-end 2013, global UMTS-HSPA subscriptions are expected to exceed 2 billion, rising to 2.8 billion by the end of 2014. GSM-UMTS-HSPA subscriptions provide the foundation for future evolutions to 3GPP Release 9, Release 10 and beyond with HSPA+, LTE and LTE-Advanced.

“Wireless data consumption is increasing faster now than ever before,” said Adrian Scrase, 3GPP Head of Mobile Competence Center. “Smartphone usage is experiencing higher volumes and the superior user experience offered by such devices is resulting in quickly rising demand and escalating use of wireless data applications. This is consequently driving the need for continued innovations that are supported by the efficient and successful 3GPP technology path.”


3GPP Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond: HSPA+, SAE/LTE and LTE-Advanced, is a comprehensive resource intended to assist members of the wireless industry as well as interested members of the general public in understanding details of the work in 3GPP on Release 9 and Release 10. In addition, the report further describes the features of Release 8 that were closed in March 2009.

Release 9, which is targeted for completion by March 2010, will provide increased feature functionality and performance enhancements to both HSPA and LTE. The report reviews additional multi-carrier and MIMO options for HSPA and features and enhancements to support emergency services, location services and broadcast services for LTE. Other Release 9 enhancements include those to support Home NodeB/eNodeB (i.e. femtocells), Self-Organizing/Self-Optimizing Networks (SON) and the evolution of the IP Multimedia Subsystem (IMS) architecture.

LTE will serve to unify the fixed and mobile broadband worlds. As an all IP-based technology, LTE will allow expansion of the Internet experience on mobile devices and deliver multimedia content to the screen of choice. The vast majority of leading operators, device and infrastructure manufacturers support LTE as the mobile broadband technology of the future and, according to Informa Telecoms & Media, 130 global operators have announced trials or intentions to evolve their networks to LTE. Two commercial networks have already been launched in Norway and Sweden by TeliaSonera in 2009 and as many as 20 will be launched in 2010.

“All roads lead to LTE – for GSM, CDMA, newly licensed and potentially even WiMAX mobile operators,” Pearson added. “The appeal of the 3GPP technology roadmap is no longer suited for only GSM operators.”

While work for Release 9 is nearing completion, significant progress has already been made in 3GPP on work for Release 10, which includes LTE-Advanced. In fact, 3GPP already submitted a proposal in October 2009 based on LTE-Advanced for the IMT-Advanced evaluation and certification process led by the International Telecommunication Union (ITU). The ITU has defined requirements that will officially define and certify technologies as IMT-Advanced, or 4G, and is expected to evaluate submitted proposals by standards organizations for potential certification in the 2010 timeframe; certified 4G/IMT-Advanced technology specifications are projected to be published by early 2011.

As part of Release 10, some of the key LTE-Advanced technology enhancements include carrier aggregation, multi-antenna enhancements and relays. Assuming LTE-Advanced is certified to be IMT-Advanced compliant, 3GPP targets completion of the Release 10 specification by year-end 2010.

“The white paper by 3G Americas provides an excellent overview of the work by 3GPP in determining the standards on the path to 4G,” Scrase said.

The popular white paper, 3GPP Mobile Broadband Innovation Path to 4G: Release 9, Release 10 and Beyond: HSPA+, SAE/LTE and LTE-Advanced, was written collaboratively by members of 3G Americas and is available for free download here.

Friday 29 January 2010

HSPA+ rollout updates, Jan 2010

It has been predicted that the growth of HSPA+ broadband across Europe is set to soar with the total number of subscribers set to nearly double across Europe in 2011.

A new report has predicted that by 2011 the growth of HSPA+ broadband across key European markets will soar, and could almost double compared to 2009. The number of subscribers is set to soar from twenty two million in 2009 to around forty three million in 2011. The report was released by CCS Insight.

According to the report HSPA+ broadband will be a major factor in seeing growth of one hundred percent in the to five major European markets. The report goes on to state that the European mobile broadband market will enjoy seeing both subscriber and revenue numbers double by 2011. Revenues are set to increase from around six billion Euros in 2009 to around eleven billion Euros in 2011.

Michael O’Hara, chief marketing officer at the GSMA, said: “It is clear from this report that with the right network investment, European mobile network operators will see significant growth in mobile broadband adoption in the next two years. HSPA technology will drive this rapid uptake across Europe as mobile operators and their customers continue to benefit from its expanding, vibrant and competitive ecosystem.”


HSPA+ was generally the most efficient way of upgrading use of bandwidth already in use and was likely to dominate in the short term at least, with an estimated 1.4 billion subscribers worldwide by 2013, around ten times the estimated take-up of LTE.

HSPA+ release 7, which became available last year, uses MIMO technology like that in 11n Wifi to help take the peak downlink throughput to 28Mbps, with 11Mbps on the uplink. Release 8, for which chipsets will become available this year, aggregates two carrier signals to bring peak data rates to 42Mbps on the downlink.

Release 9 will put two MIMO streams on each of two 5MHz carriers, aggregated to produce a 10MHz data pipe delivering 84Mbps on the downlink; the uplink uses simple aggregation to 23Mbps. A projected Release 10 would bring the peak downlink speed to 168Mbps, though this would require 20MHz carriers only available in the 2.5GHz and 2.6GHz bands.

Novatel Wireless, a developer of wireless data cards and other devices, said that it has added support for dual-carrier HSPA+ networks. The firm said it is using Qualcomm's MDM8220 chipset for the support, and will launch commercial devices in the second half of 2010 based on the chipset. Novatel said the new support will add more advanced data capability and other features to its offerings. Dual Carrier HSPA+ networks are expected to provide higher throughput to wireless data devices, and also helps address better service for cell phone users.

The new modem can receive data at up to 42M bps (bits per second) in compatible 3G networks. To increase the theoretical maximum download speed of the modem from 21M bps to 42M bps, Novatel uses two carrier frequencies instead of the usual one, a technique called dual-carrier. But it will only deliver the higher speed on networks that also support the technique.

Users can expect peak speeds at up to 30M bps, according to Hans Beijner, marketing manager for radio products at Ericsson.Leif-Olof Wallin, research vice president at Gartner, is a more pessimistic, saying increased traffic on the networks could negatively impact speeds. "I think it will be difficult to get above 20M bps," he said.

Sixty-six operators have said they plan to use HSPA Evolution, and so far 37 networks have been commercially launched, according to statistics from the Global Mobile Suppliers Association (GSA).

However, the version of HSPA Evolution that supports 42M bps is still very much in its infancy. Last week, mobile operator 3 Scandinavia announced plans to launch services when modems become available. In December, representatives from Vodafone and the Australian operator Telstra visited Ericsson to Stockholm to view a demonstration, but neither operator has so far announced plans to launch commercial services.

Ericsson and 3 Scandinavia have unveiled plans to roll-out a worlds-first 84Mbps HSPA+ wireless network. The initial rollout will cover Denmark and four Swedish cities. HSPA+ networks that currently operate in Canada, for example, offer speeds of up to 21Mbps depending on conditions. In the United States, T-Mobile recently announced a similar planned network.

Real-world tests of the 21Mbps networks show the services achieving around 7Mbps speed. If a similar performance could be applied to the new Ericsson/3 network, it could result in speeds of roughly 28Mbps at realistic distances and network load.

and 3 will also deploy 900MHz 3G networks in Sweden in a bid to boost coverage in remote areas, as existing higher frequency networks have left some users with poor performance.
The high-speed services will hit Denmark and areas of Sweden this winter if all goes to plan.

China Unicom is putting the finishing touch on the tests on its HSPA+ networks in Guangzhou, Shenzhen, and Zhuhai, which were kicked off in October 2009 by partnering with its three major suppliers Huawei Technologies, ZTE, and Ericsson.

HSPA+ is the next generation technology for China Unicom's WCDMA 3G service. HSPA+, also known as Evolved High-Speed Packet Access, is a wireless broadband standard defined in 3GPP release 7. The HSPA+ network claims with a transmission speed of 21Mbps, 1.5 times faster than its current 3G network.

The outdoor average speed of the networks built up by Ericsson and Huawei reach up to 16.5Mbps and 18.5Mbps on the downlink, 50% higher than that of the existing HSPA network. That means you can download a song within two or three seconds.

Cell C, South Africa, has signed a US$378m deal with the Chinese telecom equipment provider ZTE Corporation. Cell C would ever lead the industry as far as network infrastructure is concerned but it is a fact that Cell C will be the first South African operator to roll out HSPA+ technologies incorporating download speeds of up to 21Mbit/s – three times faster than anything currently available.

According to Cell C an important factor in the decision to appoint ZTE is its ability to offer 4G services using Cell C’s 900MHz frequency band which offers wider and deeper coverage than existing 2100 MHz networks, enabling cost effective deployment to rural as well as metropolitan areas.

Wednesday 13 January 2010

Takehiro Nakamura on LTE Radio Aspects


In summary:

Release 8 - Minor change requests to it based on March 2009 freeze;
Release 9 - an enhanced version of Release 8 and additional features;
Release 10 (LTE-Advanced) - proposed as an IMT-Advanced and is expected to be approved by December 2010; major differences between LTE and LTE-Advanced


Wednesday 16 December 2009

3G Americas Publishes New Report on LTE SON Self-Optimizing / Self-Organizing Networks

I have blogged about SON networks before. Now has published an educational report titled, The Benefits of SON in LTE, to increase understanding of the improvements in network management that have been developed through 3GPP standards – Release 8, Release 9 and beyond.

Self-Optimizing and Self-Organizing Networks, called SON, can significantly improve network management performance, helping operators and their customers. The 3GPP standards organization is standardizing self-optimizing and self-organizing capabilities for LTE. LTE SON will leverage network intelligence, automation and network management features in order to automate the configuration and optimization of wireless networks, thereby increasing efficiency as well as improving network performance and flexibility.

“The time is right for SON as wireless carriers’ networks have increasing mobile broadband demand and a high level of complexity,” said Chris Pearson, President of 3G Americas. “The good news is that smartphones, netbooks and emerging classes of mobile devices are driving significant growth of wireless data usage. However, operators will need to continue to significantly improve network management capabilities to efficiently meet the demands of this new mobile broadband world.”

The Benefits of SON in LTE describes the motivation behind SON and provides an overview of key SON features contained in Releases 8 and 9 that will serve as a solution for network operators. Motivations for operators to deploy SON include:

  • Wireless service providers must now support a growing number of higher-bandwidth data applications and services on their networks
  • Operators must drive down the delivery cost per bit
  • Radio access network complexity will increase through additions of small cells such as femtocells, picocells as well as WiFi access points to increase and improve coverage and capacity

These and other trends portend ever-increasing demands upon service providers in the areas of network performance and operations.

Initial solutions are offered in the 3GPP Release 8 specifications, which were completed in March 2009, and include SON features such as automatic inventory, software download, neighbor relations and PCI assignment that would be built over 3GPP network management architecture. LTE SON features begin with 3GPP Release 8 and evolve with the expected LTE network evolution stages. In 3GPP Release 9, other SON features are addressed, such as the optimization of coverage and capacity, mobility, RACH, load balancing and support of SON features in multi-vendor network environments.

Other organizations such as the Next Generation Mobile Networks (NGMN) have contributed significantly to the development and standardization of SON at 3GPP.


“Self-optimizing networks are a key part in the future-proofing of network reliability and operational efficiency,” said Dr. Peter Meissner, Operating Officer of the NGMN Alliance. “NGMN established a set of initial requirements and since then has worked with its partners to define the remaining requirements and to drive forward the early adoption in the standardization.”

You can find this whitepaper and many other whitepapers on LTE at the 3G4G Library here.


Tuesday 10 November 2009

eMBMS: Naughty after 11pm ;)


I have blogged about MBMS in past about how it didn't take off even though it was a promising technology. Now you may probably be aware that eMBMS is part of Release-9. I heard some interest in this feature.

The expectation is that the demand for data drops off later in the night after around 10pm. The operators may start some channels say after 11pm because the network will have lots of spare capacity that could be used for television channels. You could have late night movies, sports channels and adult channels.

An advantage of going eMBMS way would mean that even if you are roaming, you can have pay per view kind of approach as long as the other network is Release-9 compliant.

Interesting idea, not sure if it will take off.