IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0112816
(2008-07-15)
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등록번호 |
US-8462643
(2013-06-11)
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발명자
/ 주소 |
- Walton, J. Rodney
- Wallace, Mark S.
- Ketchum, John W.
- Howard, Steven J.
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출원인 / 주소 |
|
대리인 / 주소 |
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인용정보 |
피인용 횟수 :
74 인용 특허 :
269 |
초록
▼
A multiple-access MIMO WLAN system that employs MIMO, OFDM, and TDD. The system (1) uses a channel structure with a number of configurable transport channels, (2) supports multiple rates and transmission modes, which are configurable based on channel conditions and user terminal capabilities, (3) em
A multiple-access MIMO WLAN system that employs MIMO, OFDM, and TDD. The system (1) uses a channel structure with a number of configurable transport channels, (2) supports multiple rates and transmission modes, which are configurable based on channel conditions and user terminal capabilities, (3) employs a pilot structure with several types of pilot (e.g., beacon, MIMO, steered reference, and carrier pilots) for different functions, (4) implements rate, timing, and power control loops for proper system operation, and (5) employs random access for system access by the user terminals, fast acknowledgment, and quick resource assignments. Calibration may be performed to account for differences in the frequency responses of transmit/receive chains at the access point and user terminals. The spatial processing may then be simplified by taking advantage of the reciprocal nature of the downlink and uplink and the calibration.
대표청구항
▼
1. A method of accessing a wireless multiple-access multiple-input multiple-output (MIMO) communication system, comprising: receiving system information via a first transport channel on a downlink;transmitting an access request via a second transport channel on an uplink, wherein the access request
1. A method of accessing a wireless multiple-access multiple-input multiple-output (MIMO) communication system, comprising: receiving system information via a first transport channel on a downlink;transmitting an access request via a second transport channel on an uplink, wherein the access request is transmitted based on the received system information;monitoring the first transport channel to determine whether an acknowledgement bit is set;processing a third transport channel on the downlink for an acknowledgment of the transmitted access request if the acknowledgement bit is set; andrepeating the receiving, transmitting, and monitoring if the acknowledgment is not received within a predetermined time period. 2. The method of claim 1, wherein a plurality of access requests are transmitted. 3. The method of claim 2, wherein the plurality of access requests are transmitted at successively lower rates. 4. The method of claim 2, further comprising: waiting a pseudo-random period of time prior to transmitting a next access request among the plurality of access requests. 5. The method of claim 2, further comprising: transmitting a steered pilot along with the access request on the second transport channel, the steered pilot being sent on at least one eigenmode of a MIMO channel for the uplink. 6. The method of claim 1, wherein the system information indicates a time interval in which transmission of access requests is allowed, and wherein the access request is transmitted within the time interval. 7. The method of claim 1, wherein the system information indicates a particular number of slots in which transmission of access requests is allowed, and wherein the access request identifies a specific slot in which the access request is transmitted. 8. The method of claim 7, wherein the slots have a time duration configurable by the system. 9. An apparatus in a wireless multiple-access multiple-input multiple-output (MIMO) communication system, comprising: a receive data processor operative to receive system information via a first transport channel on a downlink;a transmit data processor operative to process an access request for transmission via a second transport channel on an uplink, wherein the access request is transmitted based on the received system information; anda controller operative to monitor the first transport channel to determine whether an acknowledgement bit is set and to direct the receive data processor to process a third transport channel on the downlink for an acknowledgment of the transmitted access request if the acknowledgement bit is set,wherein the receive data processor is operative to receive updated system information, the transmit data processor is operative to process another access request, and the controller is operative to monitor the first transport channel if the acknowledgment is not received within a predetermined time period. 10. The apparatus of claim 9, wherein a plurality of access requests are transmitted. 11. The apparatus of claim 10, wherein the plurality of access requests are transmitted at successively lower rates. 12. The apparatus of claim 10, wherein the controller is operative to wait a pseudo-random period of time prior to initiating transmission of a next access request among the plurality of access requests. 13. The apparatus of claim 10, further comprising: a transmit spatial processor operative to transmit a steered pilot along with the access request on the second transport channel, the steered pilot being sent on at least one eigenmode of a MIMO channel for the uplink. 14. An apparatus in a wireless multiple-access multiple-input multiple-output (MIMO) communication system, comprising: means for receiving system information via a first transport channel on a downlink;means for transmitting an access request via a second transport channel on an uplink, wherein the access request is transmitted based on the received system information;means for monitoring the first transport channel to determine whether an acknowledgement bit is set; andmeans for processing a third transport channel on the downlink for an acknowledgment of the transmitted access request if the acknowledgement bit is set,wherein the means for receiving receives updated system information, the means for transmitting processes another access request, and the means for monitoring monitors the first transport channel if the acknowledgement is not received within a predetermined time period. 15. The apparatus of claim 14, wherein a plurality of access requests are transmitted. 16. The apparatus of claim 15, wherein the plurality of access requests are transmitted at successively lower rates. 17. The apparatus of claim 15, further comprising: means for waiting a pseudo-random period of time prior to transmitting a next access request among the plurality of access requests. 18. The apparatus of claim 15, further comprising: means for transmitting a steered pilot along with the access request on the second transport channel, the steered pilot being sent on at least one eigenmode of a MIMO channel for the uplink. 19. A computer-program product used use in a wireless multiple-access multiple-input multiple-output (MIMO) communication system comprising a non-transitory computer readable medium having a set of instructions stored thereon, the set of instructions being executable by one or more processors and the set of instructions comprising: instructions for receiving system information via a first transport channel on a downlink;instructions for transmitting an access request via a second transport channel on an uplink, wherein the access request is transmitted based on the received system information;instructions for monitoring the first transport channel to determine whether an acknowledgment bit is set;instructions for processing a third transport channel on the downlink for an acknowledgment of the transmitted access request if the acknowledgement bit is set; andinstructions for repeating the receiving, transmitting, and monitoring if the acknowledgment is not received within a predetermined time period. 20. The computer-program product of claim 19, wherein a plurality of access requests are transmitted. 21. The computer-program product of claim 20, wherein the plurality of access requests are transmitted at successively lower rates. 22. The computer-program product of claim 20, further comprising: instructions for waiting a pseudo-random period of time prior to transmitting a next access request among the plurality of access requests. 23. The computer-program product of claim 20, further comprising: instructions for transmitting a steered pilot along with the access request on the second transport channel, the steered pilot being sent on at least one eigenmode of a MIMO channel for the uplink.
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