Wednesday, November 30, 2011

Reducing CSFB Timing with RRC R9 Optimisations

While in the initial testing CSFB timing used to be between 6-8 seconds, most Rel-8 phones can complete the CSFB procedure between 4-4.5 seconds. Unfortunately this is still a lot in terms of signalling. To reduce this in Rel-9 there is a simple optimisation that has been done.
In the RRC Connection Release message, there is a possibility to add UTRAN/GERAN System Information messages. In the picture above, I have only shown UTRA System Information but a similar picture can be drawn for GERAN.

Once all the Mandatory SIB's are sent to the UE then it can immediately camp on without the need to read any other additional system info. This will reduce the CSFB time between 1-2 seconds.

The lesser the CSFB time, the better the Quality of end user experience

Tuesday, November 29, 2011

Nice Pie Chart on different Android Devices

Click to enlarge

I guess Pie charts like these can convey more information then writing about the percentages of devices sold. Maybe we should use them more often to represent information.

Source: From a presentation by Deutsche Bank in the 4th LTE North America Conference, 8 - 9 November 2011, Dallas, Texas, USA

Saturday, November 26, 2011

LTE Capacity Analysis


From the 4th LTE North America Conference, 8 - 9 November 2011, Dallas, Texas, USA
Presented by Bill Ingram, Cricket Communications, November 8, 2011

Wednesday, November 23, 2011

Secure Wi-Fi for Large Scale Events and Arenas

Interesting presentation from Logica on Secure WiFi. The resolution of this presentation is low for security reasons as well, I guess.
To download this presentation and other presentation from the recent event, click here.

Monday, November 21, 2011

HSDPA multiflow data transmission

From RP-111375:

HSPA based mobile internet offerings are becoming very popular and data usage is increasing rapidly. As a result, HSPA has begun to be deployed on more than one transmit antenna and/or on more than one carrier. As an example, the single cell downlink MIMO (MIMO-Physical layer) feature was introduced in Release 7. This feature allowed a NodeB to transmit two transport blocks to a single UE from the same cell on a pair of transmit antennas thus improving data rates at high geometries and providing a beamforming advantage to the UE in low geometry conditions. Subsequently, in Release-8 and Release-9, the dual cell HSDPA (DC-HSDPA) and dual band DC-HSDPA features were introduced. Both these features allow the NodeB to serve one or more users by simultaneous operation of HSDPA on two different carrier frequencies in two geographically overlapping cells, thus improving the user experience across the entire cell coverage area.

When a UE falls into the softer or soft handover coverage region of two cells on the same carrier frequency, the link from the serving HS-DSCH cell is capacity or coverage limited and the non-serving cell in its active set has available resources, it would be beneficial to schedule packets to this UE also from the non-serving cell and thereby improve this particular user’s experience.


One family of such schemes parses the incoming data for the user into multiple (restricted to two cells in the study) data streams or flows, each of which is transmitted from a different cell [8] Concurrent transmission of data from the two cells may either be permitted or the UE may be restricted to receiving data from only one cell during a given TTI. The former type of scheme is designated an aggregation scheme while the latter is termed a switching scheme. The aggregation scheme can be seen as subsuming the switching scheme at the network when scheduling to the user is restricted to the cell with better channel quality.

Figure 14 illustrates the basic multi-flow concept with both cells operating on the same carrier frequency F1.




3GPP studied different multipoint transmission options for HSDPA and documented the findings and performance gains in TR25.872 providing feasibility and performance justification for the specification work.

For more details also see:
http://www.3gpp.org/ftp/Specs/html-info/FeatureOrStudyItemFile-530034.htm
See also old blog post on Multipoint HSDPA/HSPA here.

Sunday, November 20, 2011

Do we need Fiber?


Click on the image to view full size


From a presentation by Acreo, available here.