Monday, 27 January 2014

Quortus: Evolving architectures for Small Cells in the Enterprise


Continuing on our theme of Enterprise Small cells, here is slightly old presentation by Quortus from the Small Cell World Summit 2013



Thursday, 23 January 2014

Sunday, 19 January 2014

Dual-connectivity, Bearer split and other Release-12 small cell enhancements


3GPP TR 36.842 has some interesting details on the small cells enhancements for Release-12. There is too much details for me to go through at the moment but there is some discussions. One of them is on the Dual connectivity and another is Bearer split. The concept of Master eNB (MeNB) and Secondary eNB (SeNB) seems to have been introduced. Here are some interesting definitions:

Bearer Split: in dual connectivity, refers to the ability to split a bearer over multiple eNBs.
Dual Connectivity: Operation where a given UE consumes radio resources provided by at least two different network points (Master and Secondary eNBs) connected with non-ideal backhaul while in RRC_CONNECTED.
Master Cell Group: the group of the serving cells associated with the MeNB.
Master eNB: in dual connectivity, the eNB which terminates at least S1-MME and therefore act as mobility anchor towards the CN.
Secondary Cell Group: the group of the serving cells associated with the SeNB.
Secondary eNB: in dual connectivity, an eNB providing additional radio resources for the UE, which is not the Master eNB.
Xn: interface between MeNB and SeNB. Since the current E-UTRAN architecture was selected as baseline in this study, Xn in this TR means X2.


There is also the concept of RRC diversity which can help mobility. as per 36.842

RRC diversity is a potential solution for improving mobility robustness. With RRC diversity, the handover related RRC signalling could additionally be transmitted from or to a potential target cell as illustrated in Figure 7.1.3-1.  RLF could in this case be prevented as long as the UE is able to maintain a connection to at least one of the cells.  This will eventually lead to a more successful handover performance (i.e. avoiding UE RRC re-establishment procedure). The RRC diversity scheme could also be applied for handovers from the macro to pico cells, between macro or between pico cells.

Finally, the security aspects for this Bearer split and dual connectivity is also being discussed. See the latest Rel-12 security update here.

Sunday, 12 January 2014

Carrier Wi-Fi: Automatic handovers in the next generation Wi-Fi


Ericsson published a paper in their journal last month about how the next generation of Wi-Fi and its integration in the 3GPP core would help moving between Wi-Fi networks and the Cellular network seamlessly.

People who read the 3G4G blog regularly would know that this is done using the Access Network Discovery and Selection Function (ANDSF). For details see here.

Another post from the 3G4G blog explains the key challenges in moving between the Cellular and Wi-Fi technology. If not done properly, the QoE can be really off putting for the end user.

The Ericsson paper highlights the following as the top-three priorities for the next generation carrier Wi-Fi:


  • Traffic steering 3GPP/Wi-Fi – to maintain optimal selection of an access network so quality of experience can be ensured and data throughput maintained;
  • Authentication – to provide radio-access network security for both SIM- and non-SIM-based devices; and
  • DPI, support for unified billing and support for seamless handover – achieved by integrating with the core infrastructure already deployed for 3GPP access.


3GPP has been working extensively in the new releases to come up with new features that would solve some of the issues and limitations that is affecting widespread deployment of carrier Wi-Fi and seamless roaming between the different technologies. Sometime back I provided the list of the features that are being released as part of different 3GPP releases, available here.

The Ericsson paper is available on Slideshare, embedded below: