Method of subscriber network load balancing in celular network

Bak R.I., Tchaikovsky I.B., Burachok R.A.

Lviv Polytechnic National University

This paper is devoted to the solving the problem which occurs in cellular networks at times of peak busy hour when the radio resources are ended in one or more cells. Proposed method increases the availability of radio resources of mobile network through radio resources forced redistribution. Radio resources forced redistribution is transfer of a part of network load from congested sector to lower loaded sector. This is done by transferring subscriber load (forced handover) between closely-spaced sectors within the common coverage area. To perform a forced handover is necessary to the power of the signal that the user receives from a base station of destination sector was equal to or above the minimum operating value and the movement of the user was negligible relative to the radius of the cell during the average duration of a communication session. Classification of active subscribers at speeds of movement (the lower the speed, the higher the priority for forced handover) and class of service (the lower the rating, the higher the priority for forced handover) is made to limit the dimension of the problem of radio resource forced redistribution. The set of mobile network sectors is represented by a network graph. In this graph each node is a sector of the cell. Connecting nodes indicate the existence of a common coverage area for the relevant sectors. This connection is a prerequisite for the forced redistribution of network radio resource. Edge weighting coefficients indicate the value of bandwidth used by subscribers of one sector, when the signal power level from second sector is equal to or greater than the minimum operating value for these subscribers. Subscriber load balancing algorithm in a mobile network consists of five steps. Scanning the sector  with the highest factor loading . Finding routes set  from node  to node , in which the paths bandwidth is not less than , and the load factor the sector  would not exceed  value after transferring to it the loads . Searching in the set  the path  with the minimum rank . Selecting subscribers in each node of the way  (except the sector ), which will change the service sector. Transferring the user's load from the sector  to the sector  is a forced handover of the subscribers on the  way, starting from the penultimate node in , and ending from the  to the second node. For systems with more computing power complicated graph is offered, which allows to perform load balancing of mobile network more effectively.