Monday 1 October 2012

LTE: What is a Tracking Area

Even though I have known tracking area for a long time, the other day I struggled to explain exactly what it is. I found a good explanation in this new book 'An Introduction to LTE: LTE, LTE-Advanced, SAE and 4G Mobile Communications By Christopher Cox'. An extract from the book and Google embed is as follows:

The EPC is divided into three different types of geographical area, which are illustrated in Figure 2.6. (see Embed below).

An MME pool area is an area through which the mobile can move without a change of serving MME. Every pool area is controlled by one or more MMEs, while every base station is connected to all the MMEs in a pool area by means of the S1-MME interface. Pool areas can also overlap. Typically, a network operator might configure a pool area to cover a large region of the network such as a major city and might add MMEs to the pool as the signalling load in that city increases.

Similarly, an S-GW service area is an area served by one or more serving gateways, through which the mobile can move without a change of serving gateway. Every base station is connected to all the serving gateways in a service area by means of the S1-U interface. S-GW service areas do not necessarily correspond to MME pool areas.

MME pool areas and S-GW service areas are both made from smaller, non-overlapping units known as tracking areas (TAs). These are used to track the locations of mobiles that are on standby and are similar to the location and routing areas from UMTS and GSM.

Tuesday 25 September 2012

LTE, M2M Device Addressing and IMSI


I was made aware of the following statement on the Verizon wireless brochure:

LTE’s inherent support for IPV6 addressing and IMSI-based telephone number identifiers makes mass deployments over LTE more easily achievable. The deployment of large numbers of mobile devices (think tens of thousands) becomes much more feasible because of LTE’s use of 15-digit IMSI telephone number identifiers for large-scale deployments, such as M2M or embedded wireless applications. 3G network technologies were limited by their use of 10-digit telephone number identifiers, which made large-scale deployments more difficult. With LTE, mass deployment of wireless services and applications, such as VoIP, smart metering, vending, and telematics, is now practical.

Now we know about the much touted 50 Billion connections by 2025 of which the majority would be M2M devices. So how are we going to handle the issue of addressing these many devices.

In the earlier presentation here, there was a mention of the direction for the solution as below:





The IMSI structure is as shown above. So depending on how it is used this can help alleviate the number shortage problem. 3GPP TR 23.888 gives the following information:


5.13      Key Issue - MTC Identifiers

5.13.1    Use Case Description

The amount of MTC Devices is expected to become 2 orders of magnitude higher than the amount of devices for human to human communication scenarios. This has to be taken into account for IMSI, IMEI and MSISDN. Regulatory bodies indicate shortages of IMSIs and MSISDNs.
The MTC Feature PS Only in TS 22.368 [2] includes a requirement that PS Only subscriptions shall be possible without an MSISDN. In principle an MSISDN is not used in any of the PS based signalling procedures. However, it will have to be assured that all PS procedures indeed work and subscriptions can be uniquely identified without providing an MSISDN. Furthermore, TS 22.368 [2] specifies that remote MTC Device configuration shall be supported for PS only subscriptions without an MSDISDN assigned. Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs. So a solution to support remote MTC Device configuration that does not require the use of MSISDNs is needed.
The identifiers can be categorised into:
-     Internal Identifiers: used within the 3GPP system to identify a UE using a subscription (or the subscription itself e.g. when the UE is not registered).
-     External Identifiers: used from outside the 3GPP system (e.g. at the MTCsp interface), to refer to a UE using a subscription (or the subscription itself e.g. when the UE is not registered).

5.13.2    Required Functionality

-     It shall be possible to uniquely identify the ME.
NOTE 1:   This requirement relates to the ME which is generally identified by the IMEI.
-     It shall be possible to uniquely identify the UE using a subscription or the subscription itself.
NOTE 2:   The two requirements above also apply to human-to-human communications. However, for Machine-Type Communication identifiers will have to be able to cater for a number of identifiers up to two orders of magnitude higher than for human-to-human communications.
-     It shall be possible to use the following identifiers:
1.       IMSI, for internal usage within the 3GPP operator domain, and either
2.       E.164 MSISDN, for usage outside the 3GPP operator domain, or
3.       Unique identifier (e.g. FQDN), other than E.164 MSISDN, for usage outside the 3GPP operator domain.
NOTE 3: Use of IMSI outside the 3GPP operator domain is an operator option (i.e. not subject to standardization)
-     If no (unique or common) MSISDN is assigned to a PS only subscription, the Internal Identifier (IMSI) shall be used as charging identifier.
-     It shall be possible to associate one or more External Identifiers to the same Internal Identifier (e.g. several MSISDNs associated with the same IMSI).
-     Globally unique External Identifiers shall be supported for identifying UEs used for MTC that must be globally reachable (i.e. irrespective of which mobile operator owns the subscription)
-     Operator specific External Identifiers (e.g. based on a private numbering plan) may be supported for identifying UEs used for MTC that have to be reachable only from the operator domain to which they are subscribed.
-     The Internal Identifier shall be globally unique.
-     Remote MTC Device configuration shall still be supported for subscriptions without an MSISDN.
NOTE 4:   Current remote MTC Device configuration solutions (i.e. Device Management and Over-the-Air configuration) are based on SMS, which assumes the use of MSISDNs.


Any more information on this subject, more than welcome.

Wednesday 19 September 2012

"No-Edge Networks" and Multi-Stream Aggregation (MSA)

The following is from Huawei press release:


The LTE-Advanced Multi-Stream Aggregation (MSA) technology standard is capable of increasing data rates at the cell's edge. A key component of Huawei's "No-Edge Networks" concept, MSA technology coordinates macro cells to improve user data rates at the cell's edge and also between heterogeneous networking scenarios to improve peak rates and simplify mobile management to ensure a consistent user experience.

With the development of mobile broadband, operators are mostly concerned about user experience. With mobile coverage, should able to enjoy the same quality of services no matter where they are. However, with mobile communication systems, the most challenging issue is system performance at the cell's edge.

The concept behind Huawei's MSA technology is that the user is always able to receive downlink data and aggregate downlink data streams from a cell or cell group with the best signal quality. A similar method applies to uplink data, where the user always transmits uplink data to a cell or cell group with the best signal quality. The uplink data streams are aggregated on the network side.

Huawei's MSA technology reduces the number of handovers, lowering device power transmission and increasing device standby time. These advantages are in accordance with the concept of delivering a "borderless network" and "green" wireless communications. It's expected that MSA technology will improve system performance at the cell's edge by almost 30%.

MSA technology is especially suitable for macro-micro HetNets. In hotspot area, macro cells provide basic LTE coverage while the micro cells provides capacity enhancement. The use of MSA technology allows users to receive controlled signaling from macro cells and services from best quality HetNet cell. Users at any location within the network can then enjoy fast and stable data services with ultra broadband, zero waiting and ubiquitous connectivity. MSA technology brings users high speeds and high quality as well as a simple service experience.

The advanced MSA technology proposed by Huawei is set to become a key feature of the evolution to 3GPP LTE-Advanced standards. Huawei has contributed 293 core standards to the 3GPP LTE/LTE-Advanced standardization process, 20% of the global total and the most of any other company.

I wasnt able to find much information but there is this couple of slides that were submitted in Rel-12 workshop that is embedded below:




What do you think of this feature?

Tuesday 18 September 2012

Tech Quotes we should know about - #TechQuotes



“My God, it's full of stars!” - David Bowman 2001: A Space Odyssey



Clarke's Three Laws:

Arthur C. Clarke formulated the following three "laws" of prediction:

  • When a distinguished but  elderly scientist states that something is possible, he is almost  certainly right. When he states that something is impossible, he is  probably wrong.
  • The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
  • Any sufficiently advanced technology is indistinguishable from magic.



“Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases:
1. It's completely impossible.
2. It's possible, but it's not worth doing.
3. I said it was a good idea all along.”
Arthur C Clarke


“Anyone who has lost track of time when using a computer knows the propensity to dream, the urge to make dreams come true and the tendency to miss lunch.” -  Tim Berners-Lee


“The future is already here.”
“It’s just not evenly distributed.”
William Gibson


“Computers make excellent and efficient servants, but I have no wish to serve under them.” - Spock, Star Trek


Technological progress is like an axe in the hands of a pathological criminal. - Albert Einstein 


If we knew what it was we were doing, it would not be called research, would it? - Albert Einstein 


"Nothing is withheld from us what we have conceived to do." - Russell Kirsch, inventor of the first internally programmable computer and process for displaying images digitally 


The best way to predict the future is to invent it.  -- Alan Kay




"Man is the lowest-cost, 150-pound, nonlinear, all-purpose computer system which can be mass-produced by unskilled labor." - NASA in 1965


“New technology is common, new thinking is rare.” - Sir Peter Blake



“The interface between man and machine … is more important than the power of the man or the power of the machine in determining overall capability.” — Shyam Sankar


Further Reading:


Please feel free to add more quotes sites via comments.

Sunday 16 September 2012

10 Billion out of 50 Billion - The Connected World


Remember the mantra of 50 Billion connected devices (blogged here and here) but 202x, apparently 10Billion are already here. The above slide is from a latest presentation by Chetan Sharma Consulting (embedded below). There are already 7 Billion mobile devices (phones + dongles) and 3 Billion others. The number of others will increase with M2M being the main focus and is touted as the next big thing, especially with LTE. 3GPP is focussing very heavily on standardising the MTC and is working on new features in upcoming releases.

Coming back to the topic of connected world, the presentation is embedded below and is a good read.