Traffic Distribution Assessment for use in SON
Publication Date: 2014-Nov-25
The IP.com Prior Art Database
Randall, Peter: INVENTOR [+3]
See attached PPT which contains all the details of the disclosure. In essence, a neighbour of a loaded cell will report, on request, the distribution of PRB usage within its coverage to the loaded cell.
By P Randall, S Burley, P Stephens
The current 3GPP standards support passing load information from a neighbour cell to the source cell for SON LB purposes.
However, in a single frequency network, load balancing is dependent on the availability of reusable PRBs between Cells.
UEs close to the Cell can operate at lower power, so their PRBs are less likely to interfere with, or receive interference from surrounding Cells, therefore a Cell in which the majority of traffic is close to the site, is better able to support Load Balancing than a cell where much of the traffic is near the Cell edge.
This paper describes a method for categorising the Cells Load Balancing capability according to traffic distribution and the resulting use of that categorisation for Load Balancing
Existing proposals on Mobility Load Balancing are based on a simple adjustment of the handover border between Cells moving whatever traffic is in that area.
This paper describes a new approach that intelligently selects the UE sessions for Load Balancing according to a matrix of the suitability of the UE locations and potential target Cell conditions.
Current standards only have neighbour cells reporting overall availability of PRB resource, however, this picture is inaccurate as there may be interferers close by that restrict that availability
The loaded cell can evaluate which of its UEs are within sufficient coverage of each neighbour cell, and determine the resources required by those UEs (#PRBs). Through suitably configuring the MRs sent by the UE this information can easily be obtained, assuming they are started early enough (i.e. before the site is swamped).
Ideally would also like to estimate if there would be a coding scheme change due to the handover (e.g. 64QAM-to-QPSK) as this may alter the PRB requirements post-HO.
When reporting PRB availability, neighbour cell needs to focus on the region where traffic would be arriving from, and not overall cell availability.
The proposed solution is best described through a simple example. Consider the simple cellular network in Figure 1.
Figure 1: Simple cellular network
Cell A is loaded. It needs to make an estimation of the availability of PRBs in regions of coverage in neighbouring cells.
Neighbour cells should report to the loaded cell the amount (or percentage) of PRBs in use for each of the areas shown in Figure 1.
Cells need to know the absolute capacity of their neighbours.
Loaded cell can estimate UE coding scheme changes post-HO based on what coding scheme it has applied for similar signal levels as reported by the UE for the target cell and adjust accordingly (noting that it can go either up or down).
When cell A has all the information from its neighbours, it looks for PRB usage in areas which are potential interferers with candidate cells target region – e.g. UEs camped on cell C...