The IP.com Prior Art Database
© 2005, Motorola, Inc.
English (United States)
5 pages / 206.5 KB
FOR DEFENSIVE PUBLICATION
Date: 31 July, 2003
Title: Forced Handover Due to Backhaul Resource Congestion
Docket No.: CE11560R
Name: Sowbhagya Rao
Name: Andrew Chu
Forced Handover Due to Backhaul Resource Congestion
Sowbhagya Rao, Andrew Chu
An algorithm that provides a prioritized access to the network resources and thus increases the probability of successful call establishment that is intended for authorized wireless priority users (National security/Emergency Preparedness personnel) to facilitate emergency and recovery response during disastrous events (floods, earthquakes, terrorist attacks, etc.). The Wireless Priority Service features are deployed within the
United Statesby the National Communication System (NCS) for GSM (Global System for Mobile Communications).
Handover algorithm in a GSM based system increases the probability of
successful call establishment for high priority call requests (emergency and
other wireless priority calls) by initiating a handover for the incoming high
priority call request
when the system is overloaded with interconnect traffic that could potentially cause T1 or E1 backhaul resource congestion in the network infrastructure while the call assignment is in progress. This feature provides additional cost benefits to the network operator by optimal usage of T1/E1 resources.
In the current iDEN system, there is no direct mapping of RF timeslots to the backhaul resources, thereby enabling system operators to reserve fewer backhaul resources than RF resources for interconnect traffic which could increase call blockings. Backhaul may also be undersized because of circuit and packet traffic partition.
Prior art related to the current solution are:
MobileCommunication Congestion Control. This does not address call priorities nor trigger HO due to backhaul congestion
2. “Directed Retry Handover” in Motorola GSM BTS. Initiates handover at call setup if closest cell is out of (radio) resources.
US6,226,277 (Lucent) – Method for Admitting New Connections Based on Usage Priorities. It drops the traffic with the lowest priority.
There could be few workarounds to ensure that the high priority call request will be successfully established, for example:
1. Increase backhaul capacity by adding additional T1s that could involve more costs
2. Preempt lower priority calls to accommodate the high priority requests, which might not be desirable.
The high priority call will be handed over to a neighboring cell (but on a different BTS) under the control of the same BSC if there is backhaul resource congestion in the system. In order to minimize the interface changes betwe...