Adaptive scheduling of voice traffic in a multi-carrier communication environment

• US 9,572,172 B2
• Filed: 11/18/2015
• Issued: 02/14/2017
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Wu, Jianming, Tong, Wen, Zhu, Peiying
• Primary Examiner(s): Zaidi, Iqbal
• Application Number:
  US14/944,370
• Publication Number:
  US 20160081104A1
• Time in Patent Office: 454 Days
• Field of Search: 370/254, 370328-339, 370/401, 709227-231
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• 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: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

The present invention provides a technique for scheduling data, and in particular, scheduling real-time or voice data for transmissions during a transmit time interval in a multi-carrier communication environment. For each transmit time interval, channel condition indicia for multiple users is determined, and an iterative scheduling process is then implemented based in part on the channel condition indicia. The iterative scheduling initially pre-assigns select tones for each of the remaining users that have not been permanently assigned tones for the given transmit time interval. Next, the remaining user having the least favorable channel conditions is selected as an active user. The newly selected active user is then permanently assigned the select tones that were initially pre-assigned to that particular user. The permanently assigned tones are removed from consideration, and the process is repeated until all the remaining users are permanently assigned unique tones for scheduling.

Claims

1. A method for scheduling data for transmission during a transmit time interval in a wireless multi-carrier communication environment, the method comprising:

for a transmit time interval;

assigning at least one respective tone from a plurality of tones to each mobile terminal of a plurality of mobile terminals, wherein the assigned at least one respective tone is different for each mobile terminal;

selecting, subsequent to assigning at least one respective tone to each mobile terminal, from the plurality of mobile terminals, an active mobile terminal based at least in part on a predetermined indicator of channel conditions;

excluding the active mobile terminal from the plurality of mobile terminals, leaving one or more remaining mobile terminals of the plurality of mobile terminals;

excluding the at least one respective tone assigned to the active mobile terminal from the plurality of tones, leaving available tones of the plurality of tones; and

assigning at least one respective tone from the available tones to at least one mobile terminal of the remaining mobile terminals.

2. The method of claim 1, wherein selecting the active mobile terminal based at least in part on the predetermined indicator of the channel conditions comprises selecting a mobile terminal associated with respective channel conditions deemed least favorable with respect to respective channel conditions of all other mobile terminals of the plurality of mobile terminals.

3. The method of claim 1, comprising performing for each respective transmit time interval of a plurality of successive transmit time intervals:

the assigning the at least one respective tone from the plurality of tones;

the selecting;

the excluding the active mobile terminal;

the excluding the at least one respective tone assigned to the active mobile terminal;

and the assigning the at least one respective tone from the available tones.

4. The method of claim 1, further comprising:

sorting tones based on channel condition information;

selecting sorted tones having channel conditions deemed most favorable; and

using the selected sorted tones as the plurality of tones.

5. The method of claim 1, wherein the assigning the at least one respective tone to each mobile terminal comprises minimizing a number of assigned tones while ensuring a target data rate is achieved based on respective channel conditions associated with the assigned at least one respective tone.

6. The method of claim 1, further comprising:

determining a number of tones for transmitting original data and a number of tones for transmitting redundant data; and

increasing the number of tones for transmitting the redundant data among each at least one respective tone assigned to a respective mobile terminal associated with poor channel conditions.

7. The method of claim 1, wherein the data scheduled for transmission comprises real-time data.

8. The method of claim 1, wherein the data scheduled for transmission comprises voice information.

9. The method of claim 1, wherein the wireless multi-cartier communication environment is a wireless orthogonal frequency division multiplexing (OFDM) communication environment and each at least one respective tone is an OFDM tone.

10. A base station comprising:

a wireless communication interface; and

control circuitry interoperating with the wireless communication interface to wirelessly transmit data during a transmit time interval in a wireless multi-carrier communication environment, wherein the control circuitry is configured to perform the following for the transmit time interval

assign at least one tone from a plurality of tones to a first mobile terminal of a plurality of mobile terminals;

remove, subsequent to the assignment of the at least one tone from the plurality of tones to the first mobile terminal of the plurality of mobile terminals, the first mobile terminal from consideration based at least in part on a predetermined indicator of respective channel conditions associated with the plurality of mobile terminals, wherein a group of remaining mobile terminals of the plurality of mobile terminals excludes the first mobile terminal;

remove the at least one tone assigned to the first mobile terminal from consideration, wherein a group of available tones of the plurality of tones excludes the at least one tone assigned to the first mobile terminal; and

assign at least one tone from the group of available tones to a second mobile terminal of the group of remaining mobile terminals.

11. The base station of claim 10, wherein the first mobile terminal is associated with respective channel conditions deemed least favorable with respect to respective channel conditions of all other mobile terminals of the plurality of mobile terminals.

12. The base station of claim 10, wherein the time interval is one of a plurality of successive time intervals, and wherein the control circuitry is configured to perform the following for each transmit time interval of the plurality of successive transmit time intervals:

assign at least one respective tone from the plurality of tones to a respective first mobile terminal of the plurality of mobile terminals;

remove the respective first mobile terminal from consideration based at least in part on a predetermined indicator of respective channel conditions associated with the plurality of mobile terminals, wherein a group of respective remaining mobile terminals of the plurality of mobile terminals excludes the respective first mobile terminal;

remove the at least one respective tone assigned to the respective first mobile terminal from consideration, wherein a group of respective available tones of the plurality of tones excludes the at least one respective tone assigned to the respective first mobile terminal; and

assign at least one respective tone from the group of respective available tones to a respective second mobile terminal of the group of respective remaining mobile terminals.

13. The base station of claim 10, wherein the control circuitry is configured to:

sort tones based on channel condition information;

select sorted tones having channel conditions deemed most favorable; and

use the selected sorted tones as the plurality of tones.

14. The base station of claim 10, wherein the control circuitry is configured to assign the at least one tone to the first mobile terminal in a manner that minimizes a number of assigned tones while ensuring a target data rate is achieved based on channel conditions associated with the assigned at least one tone.

15. The base station of claim 10, wherein the data comprises real-time data.

16. The base station of claim 10, wherein the data comprises voice information.

17. The base station of claim 10, wherein the wireless multi-carrier communication environment is a wireless orthogonal frequency division multiplexing (OFDM) communication environment and the at least one tone are OFDM tones.

18. A non-transitory memory medium storing programming instructions executable to cause a wireless communication device to:

perform tone assignment for a transmit time interval associated with wireless transmission of data in a wireless multi-carrier communication environment, wherein to cause the device to

perform the tone assignment, the programming instructions are executable to cause the wireless communication device to perform the following until there are no more remaining mobile terminals from a subset of mobile terminals of a plurality of mobile terminals;

assign a respective select tone from available tones of a plurality of tones to each remaining mobile terminal of the plurality of mobile terminals, wherein the assigned select tone is different for each mobile terminal;

select, subsequent to having assigned a respective select tone to each remaining mobile terminal, from the remaining mobile terminals, an active mobile terminal based at least in part on a predetermined indicator of respective channel conditions associated with the remaining mobile terminals;

exclude the active mobile terminal from the remaining mobile terminals; and

exclude the assigned select tone associated with the active mobile terminal from the available tones;

wherein the subset of mobile terminals comprises at least two mobile terminals of the plurality of mobile terminals.

19. The non-transitory memory medium of claim 18, wherein the programming instructions are further executable to cause the wireless communication device to:

perform the tone assignment for each transmit time interval of a plurality of successive transmit time intervals.

20. The non-transitory memory medium of claim 19, wherein the programming instructions are further executable to cause the wireless communication device to:

sort tones based on channel condition information;

select sorted tones having channel conditions deemed most favorable; and

use the selected sorted tones as the plurality of tones.