Method and system for performing call admission control in the uplink for third generation wireless communication systems

• US 20040192321A1
• Filed: 11/21/2002
• Published: 09/30/2004
• Est. Priority Date: 03/14/2002
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Zhang, Guodong
• Granted Patent: US 6,842,618 B2
• Time in Patent Office: Days
• US Class Current: 455/452.1
• CPC Class Codes: H04W 48/06 based on traffic conditions
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method and system for performing call admission control in wireless communication systems is disclosed. Resource units required by a new user are assigned based on an outage probability of each uplink timeslot. The outage probability of each timeslot is updated as the resource units are assigned so that each resource unit assignment results in the lowest possible contribution to total outage probability. Once all of the resource units are assigned, the total outage probability is computed based on the resource allocation. If the total outage probability is below a predetermined value, the new user is admitted. If the total outage probability is above the predetermined value, the new user is rejected.

Claims

1. A method for performing call admission control comprising:

assigning resource units required by a new user to timeslots based on outage probability of each individual timeslot;

computing a total outage probability for the new user;

determining whether the total outage probability is below a predetermined value; and

admitting the new user where the determination is positive.

2. A method as in claim 1 wherein the step of assigning resource units is performed by:

computing an outage probability for each timeslot;

assigning a first resource unit to the timeslot having the lowest outage probability; and

assigning subsequent resource units to timeslots that will result in the lowest total outage probability for the new user.

3. A method as in claim 2 wherein the timeslots that will result in the lowest total outage probability are selected based on each of their individual contributions to total outage probability.

4. A method for performing call admission control comprising:

computing an outage probability for each uplink timeslot;

assigning a first resource unit required by a new user to the timeslot having the lowest outage probability;

assigning subsequent resource units required by the new user to timeslots that will result in the lowest total outage probability for the new user;

computing a total outage probability based on which timeslots have been assigned resource units; and

admitting the new user if the total outage probability is below a predetermined value.

5. A method as in claim 4 wherein the timeslots that will result in the lowest total outage probability for the new user are identified by identifying the timeslots that contribute the least to the total outage probability of the user.

6. A method for performing call admission control comprising:

computing an outage probability for each timeslot;

identifying a timeslot having the lowest outage probability;

assigning a first resource unit required by a new user to the identified timeslot;

assigning subsequent resource units required by the new user to a group of timeslots that minimizes total outage probability of the new user;

computing a total outage probability based on which timeslots have been assigned resource units; and

admitting the new user if total outage probability is less than a predetermined value.

7. A method as in claim 6 wherein each timeslot in the group of timeslots is selected based on its individual contribution to total outage probability.

8. A method as in claim 6 wherein the step of assigning subsequent resources further comprises:

computing a first value indicative of the contribution to the total outage probability if a subsequent resource unit is assigned to the identified timeslot;

computing a second value indicative of the contribution to the total outage probability if a subsequent resource unit is assigned to a timeslot other than the identified timeslot;

continuing to assign subsequent resource units to the identified timeslot as long as the second value is not greater than or equal to the first value; and

assigning subsequent resource units to a timeslot other than the identified timeslot if the second value is greater than or equal to the first value.

9. A call admission control system comprising:

user equipment;

a base station; and

a radio network controller wherein the radio network controller is adapted to;

assign resource units required by a new user to a plurality of timeslots based on each timeslots individual contribution to total outage probability of the new user; and

admit the new user where the total outage probability of the new user is below a predetermined value.

10. A call admission control system as in claim 9 wherein the radio network controller is adapted to:

compute an outage probability for each uplink timeslot each time a new user seeks admission;

assign a first resource unit required by the new user to the timeslot having the lowest outage probability;

assign subsequent resource units required by the new user to a group of timeslots that will result in the lowest total outage probability for the new user; and

admit the new user if total outage probability is below a predetermined value.

11. A call admission control system as in claim 10 wherein each timeslot in the group of timeslots is selected based on its individual contribution to total outage probability.

12. A call admission control system as in claim 10 wherein the radio network controller is configured to select the group of timeslots by:

computing a first value indicative of the contribution to the total outage probability if a subsequent resource unit is assigned to the identified timeslot;

computing a second value indicative of the contribution to the total outage probability if a subsequent resource unit is assigned to a timeslot other than the identified timeslot;

continuing to assign subsequent resource units to the identified timeslot as long as the second value is not greater than or equal to the first value; and

assigning subsequent resource units to a timeslot other than the identified timeslot if the second value is greater than or equal to the first value.