METHOD FOR DYNAMIC RESOURCE ALLOCATION OF UPLINK AND DOWNLINK IN OFDMA/TDD CELLULAR SYSTEM

• US 20080076438A1
• Filed: 09/21/2007
• Published: 03/27/2008
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: INHA Industry Partnership Institute
• Original Assignee: INHA Industry Partnership Institute, POSDATA Co., Ltd (Posco)
• Inventors: Kim, Jae, Chang, Kyung, Ko, Sang, Sun, Tae
• Granted Patent: US 8,064,392 B2
• Time in Patent Office: Days
• US Class Current: 455/452.2
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 72/04 Wireless resource allocation

Abstract

Provided is a method for dynamic resource allocation of uplink and downlink in an OFDMA/TDD cellular system. The method for dynamic resource allocation of uplink in an OFDMA/TDD cellular system includes the steps of determining the number of sub-channels which can be allocated to each user through an FLR algorithm; performing channel allocation for a first frame through a round-robin algorithm in which channel information is not needed; performing dynamic channel allocation for a next frame through uplink channel information measured by uplink channel sounding; and performing power control. The method for dynamic resource allocation of downlink in an OFDMA/TDD cellular system includes the steps of selecting a user through a GPF algorithm; performing dynamic channel allocation through an ASA algorithm so as to perform a FASA algorithm for obtaining a multiuser diversity gain; and performing dynamic power allocation through an improved CHC algorithm, in consideration of a data rate provided to each user and a channel state.

Claims

1. A method for dynamic resource allocation of uplink in an OFDMA/TDD cellular system, the method comprising the steps of:

determining the number of sub-channels which can be allocated to each user through an FLR algorithm;

performing dynamic channel allocation for a first frame through a round-robin algorithm in which channel information is not needed;

performing dynamic channel allocation for a next frame through uplink channel information measured by uplink channel sounding; and

performing power control.

2. The method according to claim 1, wherein the performing of the power control includes the steps of:

judging whether a data rate requested by a user is satisfied or not;

applying a rate adaptive inner closed-loop power control algorithm to the user who transmits a smaller amount of data than a requested amount of data, if the data rate requested by the user is not satisfied; and

applying a margin adaptive inner closed-loop power control algorithm to the user who transmits a larger amount of data than a requested amount of data, if the data rate requested by the user is satisfied.

3. A method for dynamic resource allocation of downlink in an OFDMA/TDD cellular system, the method comprising the steps of:

selecting a user through a GPF algorithm;

performing dynamic channel allocation through an ASA algorithm so as to perform a FASA algorithm for obtaining a multiuser diversity gain; and

performing dynamic power allocation through an improved CHC algorithm, in consideration of a data rate provided to each user and a channel state.

4. The method according to claim 3, wherein the performing of the dynamic channel allocation includes the steps of:

searching for sub-channels which can guarantee the highest data rate to the selected user, among sub-channels which are not allocated to other users;

calculating data rates which the sub-channels can guarantee to another user; and

comparing the calculated data rates, and then allocating a sub-channel, which provides the smallest data rate to another user among the searched sub-channels, to the selected user.

5. The method according to claim 4, wherein in the searching for of the sub-channels, the sub-channel is searched for by

6. The method according to claim 4, wherein in the calculating of the data rates, the data rates are calculated by

7. The method according to claim 3, wherein the performing of the dynamic power allocation includes the steps of:

grouping users;

collecting extra power; and

re-assigning the collected extra power.

8. The method according to claim 7, wherein in the grouping of the users, users who receive a larger amount of data than at a requested data rate are designated as a first group, users who receive a smaller amount of data than at a requested data rate are designated as a second group, and users who do not even satisfy a target CINR of the lowest MCS level because of a poor channel state are designated as a third group.

9. The method according to claim 7, wherein in the collecting of the extra power, the extra power is collected little by little for several stages such that the current MCS levels of users from whom power is collected decrease.

10. The method according to claim 7, wherein in the re-assigning of the collected extra power, the collected extra power is preferentially re-assigned to a user, who has the highest MCS level, among the corresponding users, and the power is re-assigned little by little for several stages such that unnecessary power consumption is prevented.

11. The method according to claim 7, wherein in the re-assigning of the collected extra power, the re-assigning is determined in accordance with the number of sub-channels allocated to the user and is then re-assigned to the user.

12. A method for dynamic resource allocation in an OFDMA/TDD cellular system, the method comprising the steps of:

receiving a uplink channel sounding signal from a mobile terminal; and

performing an uplink sub-channel allocation based on an uplink channel information measured by the uplink channel sounding signal.

13. The method according claim 12, wherein the uplink sub-channel allocation is performed within a predetermined number of sub-channels depending on a position of the mobile terminal.