Method of dynamic transmit scheduling using channel quality feedback

• US 7,397,803 B2
• Filed: 07/08/2004
• Issued: 07/08/2008
• Est. Priority Date: 05/09/2000
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Love, Robert T., Classon, Brian K., Cudak, Mark C., Rotstein, Ron
• Primary Examiner(s): Trost; William
• Assistant Examiner(s): Ewart; James D
• Application Number:
  US10/886,962
• Publication Number:
  US 20050003847A1
• Time in Patent Office: 1,461 Days
• Field of Search: 455/9, 455/10, 455/62, 455/63.1, 455/67.11, 455/67.13, 455/423, 455/452.1, 455/452.2, 455/453, 455/504, 455/505, 455/506, 455/512, 455/343.4, 455/450, 370/230, 370/329, 370/358, 370/391, 370/395.4, 370/395.64, 370/395.65, 370/543, 370/431
• US Class Current: 370/395.4
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method and system for dynamic rate switching via medium access channel layer signaling is disclosed, wherein data rates for high data rate channels are automatically shifted up or down based on a predetermined metric. In a preferred embodiment, data rates are automatically shifted up or down based on transmit channel gain required to maintain a required signal to noise ratio.

Claims

1. A method for scheduling a plurality of mobile units for data transmission, the method comprising the steps of:

determining a plurality of mobile units that require data transmission;

determining a metric for each of the plurality of mobile units that require data transmission;

selecting, based on the metric, a mobile unit from the plurality of mobile units that require data transmission;

determining a transmission rate based on channel conditions and a coherence time left in a fade cycle, wherein determining the transmission rate comprises determining a reduced transmission rate when the coherence time left in the fade cycle indicates that a fade is probable; and

transmitting a packet at the transmission rate to the mobile unit selected.

2. A method for scheduling a plurality of mobile units for data transmission, the method comprising the steps of:

determining a plurality of mobile units that require data transmission;

determining power control feedback information for each mobile unit within the plurality of mobile units that require data transmission;

scheduling the plurality of mobile units for data transmission based on their power control feedback information, wherein scheduling comprises prioritizing at least one mobile unit of the plurality of mobile units over at least one other mobile unit of the plurality of mobile units for data transmission and wherein the power control feedback information comprises a voltage gain setting of a forward dedicated channel;

determining a metric for each of the plurality of mobile units that require data transmission;

selecting, based on the metric, a mobile unit from the plurality of mobile units that require data transmission;

determining a transmission rate based on channel conditions and a coherence time left in a fade cycle, wherein determining the transmission rate comprises determining a reduced transmission rate when the coherence time left in the fade cycle indicates that a fade is probable; and

transmitting a packet at the transmission rate to the mobile unit selected.

3. The method of claim 2 further comprises the step of determining C/I information for each mobile unit within the plurality of mobile units and scheduling the plurality of mobile units additionally based on C/I.

4. The method of claim 3 wherein the step of determining C/I information for each mobile unit comprises the step of determining feedback information of a common channel.

5. The method of claim 2 wherein the step of scheduling the plurality of mobile units for data transmission comprises the step of scheduling the plurality of mobile units for data transmission over a common channel shared by the plurality of mobile units.

6. The method of claim 2 wherein the metric includes a priority metric based on a time a packet is queued.

7. The method of claim 2 wherein the power control feedback information comprises an accumulation of power control commands.

8. An apparatus for scheduling mobile units for data transmission, the apparatus comprising:

a channel statistic estimator, wherein the channel statistic estimator has power control information for a plurality of mobile units as an input and outputs a power-control statistic based on the power control information;

a scheduler having the power-control statistic as an input and outputting scheduled mobile units based on the power control statistic, wherein the scheduled mobile units comprises at least one mobile unit of the plurality of mobile units being prioritized over at least one other mobile unit of the plurality of mobile units for data transmission and wherein the power-control statistic comprises a voltage gain setting of a forward dedicated channel;

means for determining a metric for each of the plurality of mobile units;

means for selecting, based on the metric, a mobile unit from the plurality of mobile units;

means for determining a transmission rate based on channel conditions and a coherence time left in a fade cycle, wherein the means for determining the transmission rate comprises a means for determining a reduced transmission rate when the coherence time left in the fade cycle indicates that a fade is probable; and

a transmitter adapted to transmit a packet at the transmission rate to the mobile unit selected.

9. The apparatus of claim 8 wherein the channel statistic estimator additionally has C/I feedback information for the plurality of mobile units as an input and outputs a statistic based on both power control and C/I information for each mobile unit.

10. The apparatus of claim 9 wherein the C/I information is C/I feedback information for a common channel shared by the plurality of mobile units.

11. The apparatus of claim 8 wherein the power control information comprises an accumulation of power control commands.

12. A method for scheduling a plurality of mobile units for data transmission, the method comprising the steps of:

determining a plurality of mobile units that require data transmission;

determining a fading metric for each of the plurality of mobile units that require data transmission;

determining a priority metric based on a time a packet is queued for each of the plurality of mobile units that require data transmission;

selecting, based on the fading metric and the priority metric, a mobile unit from the plurality of mobile units that require data transmission;

determining a reduced transmission rate when a coherence time left in a fade cycle indicates that a fade is probable; and

transmitting a packet at the reduced transmission rate to the mobile unit selected.

13. The method of claim 12 wherein the fading metric is based on a voltage gain setting of a forward dedicated channel.

14. The method of claim 12 wherein the fading metric is based on an accumulation of power control commands.

15. The method of claim 12 wherein the fading metric is based on measured C/I feedback.