Methods for minimizing setup time by optimizing bit allocation in multi-channel communication system

• US 20030185311A1
• Filed: 03/13/2003
• Published: 10/02/2003
• Est. Priority Date: 03/28/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Yong-Woon
• Granted Patent: US 7,274,743 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: N/A

Abstract

Methods for bit allocation and power tuning for optimizing a setup time in a multi-channel communication system. In one aspect, a bit allocation method includes measuring a signal-to-noise ratio (SNR) of each subchannel of a channel, determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, determining a sum of the greatest allocable bit numbers of the subchannels, and determining a difference between the sum of the greatest allocable bit numbers of the subchannels and a target bit number. For each subchannel, a currently allocated bit number of the subchannel is set equal to the greatest allocable bit number of the subchannel, if the difference between the sum of the greatest allocable bit numbers and the target bit number is less than or equal to a predetermined value. On the other hand, for each subchannel, a currently allocated bit number of the subchannel is set to a value that is reduced from the greatest allocable bit number of the subchannel by a predetermined ratio, if the difference between the sum of the greatest allocable bit numbers and the target bit number is greater than the predetermined value. The currently allocated bit numbers of one or more subchannels is adjusted until a sum of the currently allocated bit numbers is equal to the target bit number. In other aspect, a transmission power of one or more subchannels is adjusted to make a margin of each of the subchannels substantially conformal.

Claims

1. A method for performing bit allocation in a multi-channel communication system, comprising the steps of:

measuring a signal-to-noise ratio (SNR) of each subchannel of a channel;

determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, and determining a sum of the greatest allocable bit numbers of the subchannels;

determining a difference between the sum of the greatest allocable bit numbers of the subchannels and a target bit number;

for each subchannel, setting a currently allocated bit number of the subchannel equal to the greatest allocable bit number of the subchannel, if the difference between the sum of the greatest allocable bit numbers and the target bit number is less than or equal to a predetermined value;

for each subchannel, setting a currently allocated bit number of the subchannel to a value that is reduced from the greatest allocable bit number of the subchannel by a predetermined ratio, if the difference between the sum of the greatest allocable bit numbers and the target bit number is greater than the predetermined value; and

adjusting the currently allocated bit numbers of one or more subchannels until a sum of the currently allocated bit numbers is equal to the target bit number.

2. The method of claim 1, wherein the step of adjusting the currently allocated bit number of one or more subchannels comprises the steps of:

for each subchannel, determining a margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

comparing the sum of the currently allocated bit numbers with the target bit number;

if the sum of the currently allocated bit numbers is greater than the target bit number, selecting the subchannel having the smallest margin; and

reducing a number of the currently allocated bits of the selected subchannel by 1.

3. The method of claim 1, wherein the step of adjusting the currently allocated bit number of one or more subchannels comprises the steps of:

for each subchannel, determining a margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

comparing the sum of the currently allocated bit numbers with the target bit number;

if the sum of the currently allocated bit numbers is less than the target bit number, selecting the subchannel having the greatest margin; and

increasing a number of the currently allocated bits of the selected subchannel by 1.

4. The method of claim 1, further comprising the steps of:

for each subchannel, determining a margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

comparing the sum of the currently allocated bit numbers with the target bit number;

if the sum of the currently allocated bit numbers is equal to the target bit number, determining an average margin of the subchannels; and

for each subchannel, determining a transmission gain coefficient of the subchannel using a difference measure between the margin of the subchannel and the average margin of the subchannels.

5. A method for performing bit allocation in a multi-channel communication system, comprising the steps of:

measuring a signal-to-noise ratio (SNR) of each subchannel of a channel;

determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, and determining a sum of the greatest allocable bit numbers of the subchannels;

determining a difference between the sum of the greatest allocable bit numbers of the subchannels and the target bit number;

adjusting a system margin, if the difference between the sum of the greatest allocable bit numbers and the target bit number is more than a predetermined value;

determining a currently allocated bit number for each subchannel using the system margin; and

adjusting the currently allocated bit number of one or more subchannels until a sum of the currently allocated bit numbers of the subchannels is equal to the target bit number.

6. The method of claim 5, wherein the step of adjusting the system margin comprises adding a value of Δ

to the system margin, wherein

7. The method of claim 6, wherein the currently allocated bit number of an i^th subchannel is

8. The method of claim 5, wherein the step of adjusting the currently allocated bit number of one or more subchannels comprises the steps of:

for each subchannel, determining a margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

comparing the sum of the currently allocated bit numbers with the target bit number;

if the sum of the currently allocated bit numbers is greater than the target bit number, selecting the subchannel having the smallest margin; and

reducing the currently allocated bit number of the selected subchannel by 1.

9. The method of claim 5, wherein the step of adjusting the currently allocated bit number of one or more subchannels comprises the steps of:

for each subchannel, determining a margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

comparing the sum of the currently allocated bit numbers with the target bit number;

if the sum of the currently allocated bit numbers is less than the target bit number, selecting the subchannel having the largest margin; and

increasing the currently allocated bit number of the selected subchannel by 1.

10. The method of claim 8, wherein the margin m_i for an i^th subchannel is

11. A method for performing bit allocation in a multi-channel communication system, comprising the steps of:

measuring a signal-to-noise ratio (SNR) of each subchannel of a channel;

determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, and determining a sum of the greatest allocable bit numbers of the subchannels;

determining a difference between the sum of the greatest allocable bit numbers of the subchannels and a target bit number;

for each subchannel, setting a currently allocated bit number of the subchannel equal to the greatest allocable bit number of the subchannel, if the difference between the sum of the greatest allocable bit numbers and the target bit number is less than or equal to a predetermined value;

for each subchannel, setting a currently allocated bit number of the subchannel to a value that is reduced from the greatest allocable bit number of the subchannel by a predetermined ratio, if the difference between the sum of the greatest allocable bit numbers and the target bit number is greater than the predetermined value;

adjusting the currently allocated bit numbers of one or more subchannels until a sum of the currently allocated bit numbers is equal to the target bit number; and

adjusting a transmission power of one or more subchannels to make a margin of each of the subchannels substantially conformal.

12. The method of claim 11, wherein the step of adjusting the transmission power of one or more subchannels comprises the steps of:

for each subchannel, determining the margin of the subchannel using the currently allocated bit number and the SNR of the subchannel;

determining an average margin of the subchannels; and

for each subchannel, determining a transmission gain coefficient of the subchannel using a measure of a difference between the margin of the subchannel and the average margin.

13. The method of claim 12, wherein the margin m_i for an i^th subchannel is

14. The method of claim 13, wherein the average margin of the subchannels

15. The method of claim 14, wherein the transmission gain coefficient p_i of an i^th subchannel is

16. A multi-channel communication device, comprising:

a transmitter for transmitting data over a channel comprising a plurality of subchannels,

the transmitter comprising a bit allocation module for performing bit allocation for the subchannels, the bit allocation module comprising;

means for measuring a signal-to-noise ratio (SNR) of each subchannel of a channel;

means for determining a greatest allocable bit number of each subchannel using the measured SNR of the subchannels, and determining a sum of the greatest allocable bit numbers of the subchannels;

means for determining a difference between the sum of the greatest allocable bit numbers of the subchannels and a target bit number;

means for setting a currently allocated bit number of each subchannel to be equal to the greatest allocable bit number of the subchannel, if the difference between the sum of the greatest allocable bit numbers and the target bit number is less than or equal to a predetermined value, and for setting a currently allocated bit number of each subchannel to a value that is reduced from the greatest allocable bit number of the subchannel by a predetermined ratio, if the difference between the sum of the greatest allocable bit numbers and the target bit number is greater than the predetermined value; and

means for adjusting the currently allocated bit numbers of one or more subchannels until a sum of the currently allocated bit numbers is equal to the target bit number.

17. The device of claim 16, wherein the bit allocation module further comprises:

means for determining a margin of each subchannel using the currently allocated bit numbers and the SNRs of the subchannels;

means for determining an average margin of the subchannels; and

means for determining a transmission gain coefficient of each subchannel, wherein the transmission gain coefficient for a given subchannel is determined using a measure of a difference between the margin of the subchannel and the average margin.

18. The device of claim 17, wherein the transmitter further comprises a transmission power adjustment module for adjusting the transmission power of a subchannel using the transmission gain coefficient of the subchannel.

19. The device of claim 18, wherein the transmission power adjustment module comprises a transmission gain table that stores the transmission gain coefficients determined by the bit allocation module.