Apparatus and method for semi distributed resource allocation in a cognitive radio wireless communication system

• US 20100232307A1
• Filed: 03/11/2010
• Published: 09/16/2010
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Sungkyunkwan University Foundation For Corporate Collaboration (SungKyunKwan University)
• Original Assignee: Samsung Electronics Co. Ltd., Sungkyunkwan University Foundation For Corporate Collaboration (SungKyunKwan University)
• Inventors: Shin, Woo-Jin, Kim, Dong-In, Park, Kyoung-Youp, Lim, Eun-Taek, Kim, Sang-Bum, Kim, Ho-Dong
• Granted Patent: US 8,908,543 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 52/265 taking into account the quality of service QoS
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 72/27 between access points

Abstract

An apparatus and operation method of a Base Station (BS) for allocating a radio resource in a Cognitive Radio (CR) wireless communication system includes, when a licensed system is activated, determining whether each of User Terminals (UTs) located in a cell satisfies Quality of Service (QoS). If all of the UTs satisfy the QoS, a binary message indicating ‘on’ is broadcasted to neighbor BSs. If at least one of the UTs does not satisfy the QoS, a binary message indicating ‘off’ is broadcasted to the neighbor BSs, and when the binary message indicating ‘off’ is received from at least one of the neighbor BSs, the binary message indicating ‘off’ is broadcasted to the UTs.

Claims

1. A method of operating a Base Station (BS) in a Cognitive Radio (CR) wireless communication system, the method comprising:

when a licensed system is activated, determining whether each of User Terminals (UTs) located in a cell satisfies each of Quality of Service (QoS) requirements;

in response to determining that all of the UTs in the cell satisfy the each of QoS requirements, broadcasting a binary message indicating ‘

on’

to neighbor BSs;

in response to determining that at least one of the UTs does not satisfy at least one of the QoS requirements and an iteration level is equal to one, broadcasting a binary message indicating ‘

off’

to the neighbor BSs; and

when the binary message indicating ‘

off’

is received from at least one of the neighbor BSs, broadcasting the binary message indicating ‘

off’

to the UTs.

2. The method of claim 1, further comprising:

in response to determining that at least one of the UTs does not satisfy the each of QoS requirements and the iteration level is greater than one, determining whether the number of UTs not satisfying the at least one of the QoS requirements is greater than a previous iteration level; and

in response to determining that the number of UTs not satisfying the at least one of the QoS requirements is greater than the previous iteration level, broadcasting the binary message indicating ‘

on’

to the neighbor BSs, wherein the iteration level implies a number of times the UT iterates a maximum Tx power regulation operation using the binary message.

3. The method of claim 2, further comprising:

in response to determining that the number of UTs not satisfying the at least one of the QoS requirements is not greater than the previous iteration level, determining whether an incremental gain obtained by performing a regulation process using a Penalty Factor (PF) decreases; and

in response to determining that the incremental gain obtained by performing the regulation process using the PF decreases, broadcasting the binary message indicating ‘

on’

to the neighbor BSs.

4. The method of claim 2, wherein whether the each of the QoS requirements is satisfied is determined by using at least one of a data rate and channel quality of each UT.

5. The method of claim 2, wherein the broadcasting of the binary message to the neighbor BSs comprises transmitting a binary message comprising a format of a Co-existence Beacon Protocol (CBP) packet by using a Self-Coexistence Window (SCW) slot.

6. The method of claim 1, further comprising broadcasting the binary message indicating ‘

on’

to the UTs located in the cell when the binary message indicating ‘

on’

is received from all of the neighbor BSs.

7. A method of operating a User Terminal (UT) in a Cognitive Radio (CR) wireless communication system, the method comprising:

when a licensed system is activated, determining a per-subcarrier Transmit (Tx) power according to a water filling mechanism in such a manner that a sum rate is maximized without exceeding a current maximum Tx power;

upon receiving a binary message indicating ‘

off’

from a Base Station (BS), determining a Penalty Factor (PF) based on at least one of the current maximum Tx power, the per-subcarrier Tx power, a per-subcarrier data rate, a minimum required data rate, and a threshold coefficient for a maximum allowed data rate; and

regulating a new maximum Tx power by multiplying the PF by the current maximum Tx power.

8. The method of claim 7, wherein the determining of the PF comprises:

determining a Power Penalty (PP) parameter which is in proportion to a sum of the per-subcarrier Tx power for all subcarriers allocated to the UT and which is in inverse proportion to the current maximum Tx power;

determining a Rate Penalty (RP) parameter which increases with an increase of a sum of a ratio of a data rate for each subcarrier to the minimum required data rate and which decreases with an increase of the maximum allowed data rate coefficient;

determining a Fairness Gain (FG) parameter which is in proportion to the data rate for each subcarrier and a sum of the per-subcarrier Tx power and which is in inverse proportion to the sum of the per-subcarrier data rate and the Tx power of each subcarrier;

determining a first value which is an inverse number of a value obtained by subtracting the FG parameter from a sum of the RP parameter and the PP parameter; and

determining as the PF a smaller value between 1 and a greater value between the first value and a second value, wherein the second value is a predetermined minimum value of the PF.

9. The method of claim 7, further comprising, when uplink data is transmitted after regulating the maximum Tx power, transmitting the PF to the BS.

10. The method of claim 7, wherein determining a per-subcarrier Tx power according to a water filling mechanism comprises considering the current maximum Tx power and a Power Spectral Mask (PSM) for avoiding interference to the licensed system.

11. A Base Station (BS) apparatus in a Cognitive Radio (CR) wireless communication system, the apparatus comprising:

a first determination module configured to determine whether each of User Terminals (UTs) located in a cell satisfies each of Quality of Service (QoS) requirements when a licensed system is activated;

a second determination module configured to broadcast a binary message indicating ‘

on’

to neighbor BSs when all of the UTs satisfy the each of the QoS requirements, a binary message indicating ‘

off’

to the neighbor BSs when at least one of the UTs does not satisfy at least one of the QoS requirements and an iteration level is equal to one, and the binary message indicating ‘

off’

to the UTs when the binary message indicating ‘

off’

is received from at least one of the neighbor BSs; and

a transmitter for transmitting the binary messages.

12. The apparatus of claim 11, wherein the second determination module is further configured to:

determine when at least one of the UTs does not satisfy the at least one of the QoS requirements and the iteration level is greater than one, whether the number of UTs not satisfying the at least one of the QoS requirements is greater than a previous iteration level,

broadcast the binary message indicating ‘

on’

to the neighbor BSs when the number of UTs not satisfying the at least one of the QoS requirements is greater than the previous iteration level, and

the iteration level implies a number of times the UT iterates a maximum Tx power regulation operation using the binary message.

13. The apparatus of claim 12, wherein the second determination module is further configured to:

determine, when the number of UTs not satisfying the at least one of the QoS requirements is not greater than the previous iteration level, determine whether an incremental gain obtained by performing a regulation process using a Penalty Factor (PF) decreases, and

broadcast the binary message indicating ‘

on’

to the neighbor BSs when the incremental gain obtained by performing the regulation process using the PF decreases.

14. The apparatus of claim 12, wherein whether the each of the QoS requirements is satisfied is determined by using at least one of a data rate and channel quality of each UT.

15. The apparatus of claim 12, wherein the transmitter transmits a binary message comprising a format of a Co-existence Beacon Protocol (CBP) packet by using a Self-Coexistence Window (SCW) slot.

16. The apparatus of claim 11, wherein the second determination module is further configured to broadcast the binary message indicating ‘

on’

to the UTs located in the cell when the binary message indicating ‘

on’

is received from all of the neighborhood BSs.

17. A User Terminal (UT) apparatus in a Cognitive Radio (CR) wireless communication system, the apparatus comprising:

a determination module configured to determine a per-subcarrier Transmit (Tx) power according to a water filling mechanism in such a manner that a sum rate is maximized without exceeding a current maximum Tx power when a licensed system is activated; and

a calculation module configured to determine, upon receiving a binary message indicating ‘

off’

from a Base Station (BS), a Penalty Factor (PF) based on at least one of the current maximum Tx power, the per-subcarrier Tx power, a per-subcarrier data rate, a minimum required data rate, and a threshold coefficient for a maximum allowed data rate,

wherein the determination module regulates a new maximum Tx power by multiplying the PF by current maximum Tx power.

18. The apparatus of claim 17, wherein the calculation module is further configured to:

determine a Power Penalty (PP) parameter which is in proportion to a sum of the per-subcarrier Tx power for all subcarriers allocated to the UT and which is in inverse proportion to the maximum Tx power,

determine a Rate Penalty (RP) parameter which increases with an increase of a sum of a ratio of a data rate for each subcarrier to the minimum required data rate and which decreases with an increase of the maximum allowed data rate coefficient,

determine a Fairness Gain (FG) parameter which is in proportion to the data rate for each subcarrier and a sum of the per-subcarrier Tx power and which is in inverse proportion to the sum of the per-subcarrier data rate and the Tx power of each subcarrier,

determine a first value which is an inverse number of a value obtained by subtracting the FG parameter from a sum of the RP parameter and the PP parameter, and determine as the PF a smaller value between 1 and a greater value between the first value and a second value, wherein the second value is a predetermined minimum value of the PF.

19. The apparatus of claim 17, further comprising a transmitter configured to transmit the PF to the BS when uplink data is transmitted after regulating the maximum Tx power.

20. The apparatus of claim 17, wherein determining a per-subcarrier Tx power according to a water filling mechanism comprises considering the current maximum Tx power and a Power Spectral Mask (PSM) for avoiding interference to the licensed system.