Communicating data between an access point and multiple wireless devices over a link

• US 7,512,096 B2
• Filed: 11/24/2004
• Issued: 03/31/2009
• Est. Priority Date: 11/24/2004
• Status: Expired due to Fees

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Kuzminskiy, Alexandr, Leung, Kin, Karimi, Hamid Reza
• Primary Examiner(s): WASHINGTON, ERIKA ALISE
• Application Number:
  US10/996,617
• Publication Number:
  US 20060109814A1
• Time in Patent Office: 1,588 Days
• Field of Search: None
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The present invention provides a method and an apparatus for communicating data over a network between a communication node, for example, an access point having a first and a second antenna and a first and a second mobile station. The method comprises weighting a first data at the access point to transmit the first data using the first and second antennas so that the first mobile station only receives the first data and weighting a second data at the access point to transmit the second data using the first and second antennas so that the second mobile station only receives the second data. A space division multiple access (SDMA) module may cause a transmission protocol to transmit the first data to the first mobile station on the downlink and transmit the second data to the second mobile station in parallel to the transmission of the first data on the downlink. In a telecommunication system, this substantially simultaneous transmission of the first and second data using a similar carrier frequency in a radio frequency communication over a wireless local area network (WLAN) may increase throughput of a downlink, for example, by a factor nominally equal to the number of antennas at an access point.

Claims

1. A method for communicating data over a network between an access point having a first and a second antenna and a first and a second mobile station, the method comprising:

weighting a first data at said access point to transmit said first data using said first and second antennas so that said first mobile station only receives said first data; and

weighting a second data at said access point to transmit said second data using said first and second antennas so that said second mobile station only receives said second data;

increasing a first data rate of transmission of said first data and a second data rate of transmission of said second data using a single carrier frequency in a radio frequency communication based on a transmission protocol;

discriminating transmissions of said first and said second data on a downlink in said radio frequency communication based on a spatial dimension;

applying a space division multiple access based on said transmission protocol to said transmissions to transmit said first and said second data substantially concurrently from said access point to said first and second mobile stations, respectively;

defining at least one of said access point, said first and second mobile stations, and said downlink at least in part by Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard to establish said network including a wireless local area network;

coupling said access point to said first and second mobile stations through said wireless local area network;

estimating a first radio channel from said access point to said first mobile station over a pilot interval; and

estimating a second radio channel from said access point to said second mobile station over said pilot interval.

2. A method, as set forth in claim 1, further comprising:

initializing said transmission protocol before starting said transmissions of said first and second data over said downlink.

3. A method, as set forth in claim 2, wherein initializing said transmission protocol further comprising:

exchanging one or more protocol data units and one or more acknowledgement frames between said access point and said first mobile station and said second mobile station.

4. A method, as set forth in claim 3, wherein initializing said transmission protocol further comprising:

offsetting transmission of a first protocol data unit of said one or more protocol data units from said access point to said first mobile station relative to transmission of a second protocol data unit of said one or more protocol data units from said access point to said second mobile station by a predetermined time.

5. A method, as set forth in claim 3, wherein initializing said transmission protocol further comprising:

shifting transmission of said first data relative to transmission of said second data; and

canceling an interference based on synchronization between a first and a second acknowledgement frame of said one or more acknowledgement frames at said access point to recover said first acknowledgement frame that at least partially overlaps said second acknowledgement frame based on the shifted transmissions of said first and second data.

6. A method, as set forth in claim 5, further comprising:

re-estimating said first radio channel associated with the recovered said first acknowledgement frame.

7. A method, as set forth in claim 6, further comprising:

receiving one or more pilot symbols and one or more synchronization symbols of said first acknowledgement frame on a set of uncorrupted sub-carriers of a multiplicity of sub-carriers;

computing estimates of said first radio channel at the uncorrupted sub-carrier frequencies based on at least one of the pilot symbols and the synchronization symbols of said first acknowledgement frame received on the multiplicity uncorrupted sub-carriers; and

computing estimates of said first radio channel at a set of corrupted sub-carriers of said multiplicity of sub-carriers using the computed estimates at the uncorrupted sub-carrier frequencies.

8. A method, as set forth in claim 7, wherein computing estimates of said first radio channel at a set of corrupted sub-carriers of said multiplicity of sub-carriers using the computed estimates at the uncorrupted sub-carrier frequencies further comprises:

applying interpolation in a frequency domain based on the computed channel estimates to compute estimates of said first radio channel at a set of corrupted sub-carriers of said multiplicity of sub-carriers.

9. A method, as set forth in claim 7, wherein computing estimates of said first radio channel at a set of corrupted sub-carriers of said multiplicity of sub-carriers using the computed estimates at the uncorrupted sub-carrier frequencies further comprises:

computing estimates of said first radio channel at a set of corrupted sub-carriers of said multiplicity of sub-carriers based on the synchronization symbols of said first acknowledgement frame.

10. A method, as set forth in claim 3, further comprising:

using a time division multiple access protocol to partition a radio resource including a channel across a space division multiple access mode and a non-space division multiple access mode of said access point; and

reserving a portion of said channel for a transmission based on said space division multiple access protocol in said space division multiple access mode of said access point.

11. A method, as set forth in claim 3, wherein initializing said transmission protocol further comprises:

delaying transmission of a first one of the protocol data units from said access point to said first mobile station relative to transmission of a second one of the protocol data units from said access point to said second mobile station by a predetermined time during a first period of operation; and

delaying transmission of a third one of the protocol data units from said access point to said second mobile station relative to transmission of a fourth one of the protocol data units from said access point to said first mobile station by a predetermined time during a second period of operation.

12. A method, as set forth in claim 3, wherein initializing said transmission protocol further comprises:

alternately delaying transmissions of the protocol data units from the access point to the first and second mobile stations, respectively.

13. A method, as set forth in claim 3, wherein initializing said transmission protocol further comprises:

transmitting the protocol data units to the first and second mobile stations in a first preselected order during a first period of time and a second preselected order during a second period of time.