One of the changes being worked on and is already available in Release-11 is the Band 29. Band 29 is a special FDD band which only has a downlink component and no uplink component. The intention is that this band is available an an SCell (Secondary cell) in CA (Carrier Aggregation).
What this means is that if this is only available as an SCell, any UE that is pre-Rel-11 should not try to use this band. It should not read the system information, reference information, etc. In fact the System Information serves little or no purpose as in CA, the PCell will provide the necessary information for this SCell when adding it using the RRC Reconfiguration message. This gives rise to what 3GPP terms as New Carrier Type for LTE as defined here. An IEEE paper published not long back is embedded below that also describes this feature in detail.
The main thing to note from the IEEE paper is what they have shown as the unnecessary information being removed to make the carrier lean.
China Mobile, in their Rel-12 workshop presentation, have suggested 3 different types/possibilities for the NCT for what they call as LTE-Hi (Hi = Hotspot and Indoor).
Network energy efficiency is to a large extent an implementation issue. However, specific features of the LTE technical specifications may improve energy efficiency. This is especially true for higher-power macro sites, where a substantial part of the energy consumption of the cell site is directly or indirectly caused by the power amplifier. The energy consumption of the power amplifiers currently available is far from proportional to the power-amplifier output power. On the contrary, the power amplifier consumes a non-negligible amount of energy even at low output power, for example when only limited control signaling is being transmitted within an “empty” cell. Minimizing the transmission activity of such “always-on” signals is essential, as it allows base stations to turn off transmission circuitry when there is no data to transmit. Eliminating unnecessary transmissions also reduces interference, leading to improved data rates at low to medium load in both homogeneous as well as heterogeneous deployments. A new carrier type is considered for Release 12 to address these issues. Part of the design has already taken place within 3GPP, with transmission of cell-specific reference signals being removed in four out of five sub frames. Network energy consumption can be further improved by enhancements to idle-mode support.
Its been a while we looked at anything to do with Network Sharing. The last post with an embed from Dr. Kim Larsen presentation, has already crossed 11K+ views on slideshare. Over the last few years there has been a raft of announcements about various operators sharing their networks locally with the rivals to reduce their CAPEX as well as their OPEX. Even though I understand the reasons behind the network sharing I believe that the end consumers end up losing as they may not have a means of differentiating between the different operators on a macro cell.
Certain operators on the other hand offer differentiators like residential femtocells that can enhance indoor coverage or a tie up with WiFi hotspot providers which may provide them wi-fi access on the move. The following whitepaper from NEC is an interesting read to understanding how RAN sharing in the LTE would work.
All UEs are members of one out of ten randomly allocated mobile populations, defined as Access Classes (AC) 0 to 9. The population number is stored in the SIM/USIM. In addition, UEs may be members of one or more out of 5 special categories (Access Classes 11 to 15), also held in the SIM/USIM. These are allocated to specific high priority users as follows. (The enumeration is not meant as a priority sequence): Class 15-PLMN Staff; -"- 14-Emergency Services; -"- 13-Public Utilities (e.g. water/gas suppliers); -"- 12-Security Services; -"- 11-For PLMN Use.
Now, in case of an overload situation like emergency or congestion, the network may want to reduce the access overload in the cell. To reduce the access from the UE, the network modifies the SIB2 (SystemInformationBlockType2) that contains access barring related parameters as shown below:
For regular users with AC 0 – 9, their access is controlled by ac-BarringFactor and ac-BarringTime. The UE generates a random number
– “Rand” generated by the UE has to pass the “persistent” test in order for the UE to access. By setting ac-BarringFactor to a lower value, the access from regular user is restricted (UE must generate a “rand” that is lower than the threshold in order to access) while priority users with AC 11 – 15 can access without any restriction
For users initiating emergency calls (AC 10) their access is controlled by ac-BarringForEmergency – boolean value: barring or not
For UEs with AC 11- 15, their access is controlled by ac-BarringForSpecialAC - boolean value: barring or not.
The network (E-UTRAN) shall be able to support access control based on the type of access attempt (i.e. mobile originating data or mobile originating signalling), in which indications to the UEs are broadcasted to guide the behaviour of UE. E-UTRAN shall be able to form combinations of access control based on the type of access attempt e.g. mobile originating and mobile terminating, mobile originating, or location registration. The ‘mean duration of access control’ and the barring rate are broadcasted for each type of access attempt (i.e. mobile originating data or mobile originating signalling).
Another type of Access Control is the Service Specific Access Control (SSAC) that we have seen here before. SSAC is used to apply independent access control for telephony services (MMTEL) for mobile originating session requests from idle-mode.
Access control for CSFB provides a mechanism to prohibit UEs to access E-UTRAN to perform CSFB. It minimizes service availability degradation (i.e. radio resource shortage, congestion of fallback network) caused by mass simultaneous mobile originating requests for CSFB and increases the availability of the E-UTRAN resources for UEs accessing other services. When an operator determines that it is appropriate to apply access control for CSFB, the network may broadcast necessary information to provide access control for CSFB for each class to UEs in a specific area. The network shall be able to separately apply access control for CSFB, SSAC and enhanced Access control on E-UTRAN.
Based on the success of the recent posts on eMBMS, here and here, this final post on this topic is a look at physical layer perspective from Test and Measurement point of view. Slides kindly provided by R&S
It was interesting to hear the other day that there is an option for HD-FDD but it is still undergoing investigation and not standardised yet. From what I hear, operators are showing an interest and we may see it coming to an operator near us in the next couple of years.
The advantages are obvious but probably the only reason this was not standardised actively is probably because then peak rates often quoted when promoting technology will be halved. The economy of scale is also important and we may not see this becoming popular unless many operators decide together to push for this.
Some 4 years back, I posted my first presentation here, titled "LTE Femtocells: Stepping stone for 'killer apps' presentation". I had couple of apps in mind that I thought could benefit from both LTE and Small Cells (or Femtocells to be specific).
The first was your phone acting as a Wireless Hard Disk Drive (HDD) that can be used to store things remotely in a server somewhere. This is similar to what is known as the Cloud nowadays.
The other day when I read why LTE is suitable for cloud connectivity, I could see that my old idea could start to become a reality. The article is here. Selective abstract as follows:
The LTE network lends itself well to cloud connectivity because it:
provides high-bandwidth connections
is IP- and Ethernet-oriented, the technologies used to connect to the cloud and within data centers
offers tools that operators didn't have in 2G and 3G (such as more granular ability to manage traffic flows and a better, DPI-based view of traffic running on the network)
features low latency, which is vital to the small flows and sessions that characterize M2M communications.
The rise of both cloud services and LTE creates a virtuous cycle. Cloud services continue to grow, which helps operators sustain their LTE business model. That growth enables them to accelerate LTE investments. Then operators can support new types of enterprise services, including cloud-based applications.
To take full advantage of this opportunity, operators have to deploy the right backhaul infrastructure. In addition to IP awareness and content awareness, the right backhaul network can leverage the technical advantages that LTE presents:
flattened architecture that helps distribute compute and storage resources
seamless migration from 2G and 3G for various physical mediums and networking protocols
an increase in capacity that starts to put mobile connectivity on par with fixed broadband access.
My reasoning for Small Cell here is, in most cases when you are doing operations that require large amounts of data to be transferred, you will be indoors, either at home or in office or in a low mobility scenario. The requirement for high security and at the same time high speed data transfer that should not be affected by other users in the cell (capacity issues) can be easily solved by using a Small cell (Femtocell for indoors, Metrocell for outdoors).
The other application I had in mind was the Home Security System. I read the following on TotalTele the other day:
3UK's wholesale division on Friday detailed plans to capture high-margin machine-to-machine traffic by partnering with service providers that are likely to have higher-than-average bandwidth requirements.
As a 3G-only operator, the company cannot go after high volume, low margin M2M traffic because it typically only requires a 2G connection. However, there are opportunities to use its 3G network to address more data-hungry verticals that will generate higher traffic volumes.
"The margin on one CCTV M2M connection is more than 50 times bigger than the margin on a smart meter connection," claimed Tom Gardner, lead wholesale manager at 3UK, during Breakfast with Total Telecom in London.
"There is one CCTV camera for every 14 people in the U.K.," he said. "If I can put a SIM in every one of them I'll be a very happy man."
3UK, which on Thursday launched its Ericsson-based wholesale M2M platform, sees a big opportunity in CCTV, particularly for mobile and temporary installations at festivals, for instance. Other potentially lucrative sectors it has identified include digital signage, back-up for fixed Internet connections, and backhauling WiFi traffic from public transport.
I am sure some of you may be thinking that '3' UK uses HSPA network, not LTE, which is true. The point here is that it could be done better using LTE and Small Cells.
The reason for using LTE would be to provide higher data rates, meaning that information can be sent faster, with higher resolution and more regularly. This will help identify the problems earlier. If the CCTV is used indoors or in high usage areas, it would make sense that it connects via Small Cell to avoid creating capacity issues in the Macro network.
Here is the embed again, of my old presentation just in case if it interests you:
With regards to SI Tunneling mentioned in the presentation, I found the following in another Qualcomm whitepapers:
With Release 9 Enhanced Release with Redirection—SI Tunneling, the device follows 3GPP release 9, where SIB information can be tunneled from the target Radio Access Network (RAN) via the core network to the source RAN and be included in the redirection message sent to the device. This can avoid reading any SIBs on the target cell. The predominant solutions deployed today are based on Release 8 Release with Redirection — SIB Skipping, in order to achieve good call setup times, good reliability, and simplify deployments. It is anticipated that Release 9 Enhanced Release with Redirection will be deployed in the near future. At this time, there is not as much push for handover-based CSFB since both Release 8 Release with Redirection—SIB Skipping and Release 9 Enhanced Release with Redirection—SI Tunneling have largely addressed any call setup time issues that may have existed with the Basic Release with Redirection solution.
M2M is going to be big. With the promise of 50 Billion devices by 2020, the networks are already worried about the overloading due to signalling by millions of devices occurring at any given time. To counter this, they have been working on avoiding overloading of the network for quite some time as blogged about here.
The feature to avoid this overload is known as Extended Access Barring (EAB). For E-UTRAN, in Rel-10, a partial solution was implemented and a much better solution has been implemented in Rel-11. For GERAN a solution was implemented in Rel-10. The following presentation gives a high level overview of EAB for E-UTRAN and GERAN.
In Rel-11, a new System Information Block (SIB 14) has been added that is used specifically for EAB. Whereas in Rel-10, the UE would still send the RRCConnectionRequest, in Rel-11, the UE does not even need to do that, thereby congesting the Random Access messages.
The following is from RRC 36.331 (2012-09)
Here is my attempt to explain the difference in overload control mechanism in Rel-8, Rel-10 and Rel-11. Please note that not actual message names are used.
As usual, happy to receive feedback, comments, suggestions, etc.
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.
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.
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
The MTC Feature PS Only in TS 22.368  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 
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).
- 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
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
- It shall be possible to use
the following identifiers:
for internal usage within the 3GPP operator domain, and either
MSISDN, for usage outside the 3GPP operator domain, or
identifier (e.g. FQDN), other than E.164 MSISDN, for usage outside the 3GPP operator
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.