Wednesday, 20 July 2011

Technology Deployment and Adoption Trends

This informative slide shows the number of years it takes after the technology is launched to reach the peak volumes. Though we know this to be true for the 1G and 2G systems, I find it difficult to believe the same would be true for 3G and 4G systems.

If the LTE deployments are going to happen as per the plans then we may see the peak volumes for 3G/HSPA+ around 2016. It would be difficult to predict the same for '4G' systems as we do not know as of know what all would be part of 4G. As you would recall that LTE was supposed to be 3.9G but was too confusing so everyone adopted it as 4G. LTE-A, the real 4G, I guess would still be part of 4G. What else would end up as 4G is hard to predict so we will have to go with the prediction for the time being.

Tuesday, 19 July 2011

Dual-Mode and Multi-Mode Femtocells

Came across this slide in one of the presentations from MWC.

The Dual-Mode and maybe Multi-Mode solution (in future) may be very useful, not only from the point of view that it can serve LTE as well as 3G mobile devices but in case of a LTE mobile where for voice calls the UE may have to fall back on 3G network, if there is no 3G coverage then there would be no voice communication possible.

One of the ways to do have a voice communication in the initial phases of LTE is CS Fallback (CSFB). CSFB is possible by the UE establishing the call on UMTS or GSM network. If for some reason the coverage on those networks is non-existent then having a dual-mode femtocell can be really helpful as it would seamlessly transfer the voice call on the 3G.

Hopefully in the future when VoLTE is here these problems would be solved automatically.

The main problem that I can see with this Dual-mode or Multi-mode solution is that the operator would have to be supporting both Small Cells solution across both the networks and I guess they would be slightly expensive.

Monday, 18 July 2011

Infographic on 'The Internet of Things'

Very interesting Infographic from Cisco on the 'Internet of Things' that we have discussed before.

Since its not possible for me to put the whole Infographic here, you can check it out on Cisco blogs.

A Survey on 3GPP Hetrogeneous Networks

Available for limited time to download free from here.

Sunday, 17 July 2011

Network Mode of Operation (NMO)

Picture Source: Tektronix

The Network Mode of Operation (NMO) is also sometimes referred to as Network Operation Mode (NOM). The Network Modes have different values and interpretation in UTRAN and GERAN

In both the cases the Operation modes is decided based on the Gs interface between the CS CN (core network) a.k.a. MSC and the PS CN a.k.a. SGSN


Network Operation Mode I (NMO-I) is used when the Gs interface is present. In this case during the registration a Combined Attach (includes GPRS Attach & IMSI Attach procedures) procedure can be performed. A GMM Attach Request message with the attach type set to Combined Attach is used. Upon completion of this procedure, MM Status is IMSI Attached and GMM State is Attached.

In Network Operation Mode II (NMO-II) the GS Interface is not present. So the GMM attach procedure and the IMSI Attach (via Location Update) has to be performed seperately. This causes additional signalling.

Basic air interface signalling in case of NMO2 is shown here.


Network operation mode 1. A network which has the Gs interface implemented is referred to as being in network operation mode 1. CS and PS paging is coordinated in this mode of operation on either the GPRS or the GSM paging channel. If the mobile device has been assigned a data traffic channel then CS paging will take place over this data channel rather than the paging channel (CS or PS).

Network operation mode 2. The Gs interface is not present and there is no GPRS paging channel present. In this case, paging for CS and PS devices will be transferred over the standard GSM common control channel (CCCH) paging channel. Even if the mobile device has been assigned a packet data channel, CS paging will continue to take place over the CCCH paging channel and thus monitoring of this channel is still required.

Network operation mode 3. The Gs interface is not present. CS paging will be transferred over the CCCH paging channel. PS paging will be transferred over the packet CCCH (PCCCH) paging channel, if it exists in the cell. In this case the mobile device needs to monitor both the paging channels.

The GERAN part above is extract from the book Convergence Technologies for 3G Networks.

The Gs interface, has a number of subtle but important advantages:

During an ongoing GPRS / EDGE data transfer (TBF established), mobiles can't detect incoming voice calls and SMS messages as they are focused on receiving packets and thus can not observe the paging channel. In NMO-1, the circuit switched part of the network forwards the paging message to the packet switched side of the network which then forwards the paging message between the user data blocks while a data transfer is ongoing. Mobiles can thus receive the paging message despite the ongoing data transfer, interrupt the session and accept the voice call or SMS.

Location/Routing area updates when moving to a cell in a different location/routing area are performed much faster as the mobile only communicates with the packet switched part of the network. The packet switched network (the SGSN) then forwards the location update to the circuit switched part of the network (to the MSC) which spares the mobile from doing it itself. This is especially important for ongoing data transfers as these are interrupted for a shorter period of time.

Cell reselections from UMTS to GPRS can be executed much faster due to the same effect as described in the previous bullet. Whithout NOM-1 an Inter RAT (Radio Access Technology) cell reselection with Location and Routing Area update requires around 10 to 12 seconds. With NOM-1 the time is reduced to around 5 to 6 seconds. An important difference as this reduces the chance to miss an incoming call during the change of the radio network. Also, ongoing data transfers are interrupted for a shorter time,an additional benefit that should not be underestimated.

Tuesday, 12 July 2011

Couple of presentations on GNSS and LCS

I came across couple of presentations from International Conference on Localization and GNSS, held in Tampere, Finland, June 29-30, 2011

This first presentation by Lauri Wirola of Nokia gives good summary of standardized positioning technologies in use today. It also lists the difference between control plane and user plane positioning. The 3GPP based positioning from Rel 5 to Rel 8 has been listed. Overall a very interesting presentation.

The second presentation by Ignacio Fernández Hernández of the European Commission, gives an overview of the EU satnav programmes (Galileo, EGNOS) and current R&D status; Present some numbers and findings of the overall GNSS R&D panorama in EU and abroad; Present some trends and challenges in location technologies for the following years. Another interesting presentation I think.

Thursday, 7 July 2011

Antenna height and coverage

From a presentation by Ed Candy of '3' in FWIC.
Self explanatory.