MAPCON - Multi Access PDN Connectivity

On Monday, I read Bernard Herscovich, CEO, BelAir Networks saying the following in RCR Wireless:

Wi-Fi is obviously a way to offload data to alleviate congestion, but it also contributes to overall network profitability by delivering data at a lower cost per megabit that traditional macrocells. ABI Research estimates that carrier Wi-Fi can deliver data at 5% the cost of adding cellular capacity. Perhaps the most important driver, though, is the fact that, properly designed and architected, a carrier Wi-Fi network will deliver a consistently great user experience. The implications of that on attracting and retaining subscribers are obvious.

We've also seen cable operators taking advantage of their broadband HFC infrastructure to mount Wi-Fi APs throughout their coverage areas, offering free Wi-Fi as a sticky service to attract and retain home broadband subscribers.

At the GSMA Mobile Asia Congress, back in mid-November, 2010, KDDI's president and chairman explained that while they would be migrating to LTE, which would double their network capacity, data demand in Japan was forecast to increase by 15 times over the next five years. So LTE alone, he admitted, would not be enough. A few weeks before that, European operators, including Deutsche Telekom and Telefonica, were making similar statements at the Broadband World Forum in Paris.

It is clear that LTE alone will not be sufficient to meet ongoing mobile data demand. Technical innovation has resulted in huge capacity gains, but we're now at a point where additional bandwidth is more of a by-product of incremental spectrum. And, we all realize the finite nature of that resource. So, based on this new spectrum, LTE macrocells could deliver a 2 – 4X capacity increase. Meanwhile, ABI estimates that data capacity requirements are increasing 150% per year.

So, it's pretty clear that carriers are going to need more than just an LTE swap out to keep delivering a great user experience. They need to, as many already realize, augment their licensed spectrum with Wi-Fi. KT, the second largest mobile carrier in South Korea, claims to be offloading 67% of their mobile data traffic onto Wi-Fi. There may also be additional unlicensed spectrum made available, at least in the U.S. and the U.K., through the release of so-called white space spectrum, freed up through the switch from analog to digital TV.

It is obvious from the technology point of view that Multiple PDN connections would need to be supported when the UE is using LTE for part of data connection and Wi-Fi for other part. In fact these two (or multiple) connections should be under the control of the same EPC core that can help support seamless mobility once you move out of the WiFi hotspot.

One of the items in 3GPP Release-10 is to do with supporting of multiple Packet Data Networks (PDN) connections for a device. A Release-9 network and the UE can only support 3GPP access based connection via EPC. In Release-10 support for upto 1 non-3GPP access has been added.

FMC100044 specifies the following requirements:

• The Evolved Packet System supports the following scenarios: a single Operator offering both fixed and mobile access; different Operators collaborating to deliver services across both networks.
• The Evolved Packet System shall support the access of services from mobile network through fixed access network via interworking.
• The Evolved Packet System shall be able to support functions for connectivity, subscriber authentication, accounting, Policy Control and quality of service for interworking between the fixed broadband access and Evolved Packet Core.
• The Evolved Packet System shall optimize QoS and Policy management meaning that it shall offer minimal signalling overhead, while interworking between the fixed broadband access and Evolved Packet Core.
• The Evolved Packet System shall be able to provide an equivalent experience to users consuming services via different accesses.

The Rel-10 work item extends Rel-9 EPC to allow a UE equipped with multiple network interfaces to establish multiple PDN connections to different APNs via different access systems. The enhancements enable:

• Establishment of PDN connections to different APNs over multiple accesses. A UE opens a new PDN connection on an access that was previously unused or on one of the accesses it is already simultaneously connected to.
• Selective transfer of PDN connections between accesses. Upon inter-system handover a UE transfers only a subset of the active PDN connections from the source to the target access, with the restriction that multiple PDN connections to the same APN shall be kept in one access.
• Transfer of all PDN connections out of a certain access system. A UE that is simultaneously connected to multiple access systems moves all the active PDN connections from the source to target access, e.g. in case the UE goes out of the coverage of the source access.

This work also provides mechanisms enabling operator's control on routing of active PDN connections across available accesses.

The scope of the work is restricted to scenarios where the UE is simultaneously connected to one 3GPP access and one, and only one, non-3GPP access. The non-3GPP access can be either trusted or untrusted.

The design of the required extensions to Rel-9 EPC is based on TR 23.861 Annex A, that provides an overview of the changes that are expected in TS 23.401 and TS 23.402 for the UE to simultaneously connect to different PDNs via different access systems.

See Also:

3GPP TR 23.861: Multi access PDN connectivity and IP flow mobility

3GPP TS 22.278: Service requirements for the Evolved Packet System (EPS)

Old Blog post on Multiple PDN Connectivity

Simplified view of Heterogeneous Networks (HetNets)

A very simple picture explaining HetNets are,

To learn more about HetNet's, see my old blog post here or the Qualcomm video from yesterday here.

Qualcomm Video on LTE Advanced: Heterogeneous Networks

Wilson Street: What can femtocells do - the next big thing!

I have blogged about the Alcatel-Lucent (ALU) Femtocells in the past. Few months back I posted about their shift from using the term Femtocells to Small cells. To make everyone aware of this small cells they launched their Wilson Street experiment and are now producing some episodes to show how these small cells can play big part in everyday life.

The first two episodes are embedded below from Youtube.

The latest (3rd) episode is available on the Wilson Street Website here.

eMPS: Enhanced Multimedia Priority Service in Release-10 and beyond

The response to emergency situations (e.g., floods, hurricanes, earthquakes, terrorist attacks) depends on the communication capabilities of public networks. In most cases, emergency responders use private radio systems to aid in the logistics of providing critically needed restoration services. However, certain government and emergency management officials and other authorised users have to rely on public network services when the communication capability of the serving network may be impaired, for example due to congestion or partial network infrastructure outages, perhaps due to a direct or indirect result of the emergency situation.

Multimedia Priority Service, supported by the 3GPP system set of services and features, is one element creating the ability to deliver calls or complete sessions of a high priority nature from mobile to mobile networks, mobile to fixed networks, and fixed to mobile networks.

Requirements for the Multimedia Priority Service (MPS) have been specified in TS 22.153 for the 3GPP Release-9

The intention of MPS is to enable National Security/Emergency Preparedness (NS/EP) users (herein called Service Users) to make priority calls/sessions using the public networks during network congestion conditions. Service Users are the government-authorized personnel, emergency management officials and/or other authorized users. Effective disaster response and management rely on the Service User’s ability to communicate during congestion conditions. Service Users are expected to receive priority treatment, in support of mission critical multimedia communications.

LTE/EPC Release 9 supports IMS-based voice call origination by a Service User and voice call termination to a Service User with priority. However, mechanisms for completing a call with priority do not exist for call delivery to a regular user for a priority call originated by a Service User. MPS enhancements are needed to support priority treatment for Release 10 and beyond for call termination and for the support of packet data and multimedia services.

MPS will provide broadband IP-based multimedia services (IMS-based and non-IMS-based) over wireless networks in support of voice, video, and data services. Network support for MPS will require end-to-end priority treatment in call/session origination/termination including the Non Access Stratum (NAS) and Access Stratum (AS) signaling establishment procedures at originating/terminating network side as well as resource allocation in the core and radio networks for bearers. The MPS will also require end-to-end priority treatment in case of roaming if supported by the visiting network and if the roaming user is authorized to receive priority service.

MPS requirement is already achieved in the 3G circuit-switched network. Therefore, if the network supports CS Fallback, it is necessary to provide at least the same capability as 3G circuit switched-network in order not to degrade the level of voice service. In CS Fallback, UE initiates the fallback procedures over the LTE as specified in TS 23.272 when UE decides to use the CS voice service for mobile originating and mobile terminating calls. To achieve priority handling of CS Fallback, NAS and AS signaling establishment procedures, common for both IP-based multimedia services and CS Fallback, shall be treated in a prioritized way.

In Release-10, for LTE/EPC, the following mechanisms will be specified.

• Mechanisms to allocate resources for signaling and media with priority based on subscribed priority or based on priority indicated by service signaling.
• For a terminating IMS session over LTE, a mechanism for the network to detect priority of the session and treat it with priority.

In Release-10, for CS Fallback, the following mechanism will be specified:

• A mechanism to properly handle the priority terminating voice call and enable the target UE to establish the AS and NAS connection to fall-back to the GERAN/UTRAN/1xRTT.

For more information, see:

3GPP TR 23.854: Enhancements for Multimedia Priority Service (Release 10)

3GPP TS 22.153: Multimedia priority service (Release 10)

10 business models that rocked 2010

Very interesting read!

10 business models that rocked 2010 - by @nickdemey (boardofinnovation.com)

View more presentations from Board of Innovation (BOI).

3GPP Tutorials via 'The SpecTools'

Some of you may have noticed that the new and revamped 3GPP website have recently started offering 3GPP specs and features tutorials via The SpecTools. There is quite a lot of useful information and most of it is premium but a lot is free as well.

So the new starters or those wishing to refresh their knowledge feel free to check this out:

http://www.thespectool.com/3gpp/index.php

Heterogeneous LTE Networks and Inter-Cell Interference Coordination

An interesting paper that is more of a background to my earlier post here is available from Nomor Research and is embedded below.

Heterogeneous LTE Networks and Inter-Cell Interference Coordination

View more documents from Zahid Ghadialy.

This paper is available to download from here.

RAN mechanisms to avoid CN overload due to MTC

Machine-to-Machine (M2M) is the future and Machine-type communications (MTC) will be very important once we have billions of connected devices. I have talked in the past about the 50 Billion connected devices by 2050 and the Internet of Things.

One of the challenges of today's networks is to handle this additional signalling traffic due to MTC. One of the very important topics being discussed in 3GPP RAN meetings is 'RAN mechanisms to avoid CN overload due to MTC'. Even though it has not been finalised, its interesting to see the direction in which things are moving.

The above figure from R2-106188 shows that an extended wait time could be added in the RRC Connection Reject/Release message in case if the eNodeB is overloaded. The device can reattempt the connection once the wait time has expired.

In R2-110462, another approach is shown where Core Network (CN) is overloaded. Here a NAS Request message is sent with delay tolerant indicator a.k.a. low priority indicator. If the CN is overloaded then it can reject the request with a backoff timer. Another approach would be to send this info to the eNodeB that can do a RRC Connection Reject when new connection request is received.

All Documents from 3GPP RAN2 #72-bis are available here. Search for NIMTC for M2M related and overload related docs.

More Dilbert Humour on Cloud Computing

When I posted a Dilbert cartoon on the weekend, I expected lots of people to click on 'Not Useful' box at the bottom of the post. Honestly I got more response than I expected. Now with Cloud being talked about everywhere, I thought it would be worthwhile sticking some more old Dilbert Cloud crackers.

To combine fun with work, there are some links as well pointing to some recent Cloud based articles. Enjoy!

Ericsson CTO: cloud computing + mobile connectivity = mind-blowing innovation

Look up, it's the future: Learning to love 'the cloud'

CES2011: NEC dual-screen Android Cloud Communicator LT-W hands-on

How the Wikimedia Foundation is Using OpenStack to Build a Cloud Infrastructure

Security researcher uses Amazon cloud to hack WPA-PSK passwords

Data security must improve for the cloud to succeed

Efficiency drive will grow government outsourcing and cloud usage, says Ovum

Introducing Windows Azure

Source of Cartoons: http://dilbert.com/