Transmit diversity method and system
First Claim
1. A method for transmitting a transmission signal via an antenna array to a receiving unit of a wireless communication system, comprising:
- dividing said transmission signal into at least two signal parts;
transmitting said at least two signal parts by using transmission beams of at least two subarrays of said antenna array;
controlling the transmission beams of at least one of said two subarrays at least in part based on feedback information received from said receiving unit;
detecting channel characteristics of a transmission channel; and
changing a predetermined hopping pattern based on the detected channel characteristics of the transmission channel;
wherein said feedback information is generated based on a channel measurement using pilot channels of predetermined antenna elements of at least one of said at least two subarrays, a number of predetermined antenna elements being smaller than a total number of the antenna elements, and the receiving unit measuring the channels of all antenna elements of the antenna array based on channel measurements using only the pilot channels of the predetermined antenna elements; and
wherein at least one of said predetermined antenna elements changes between slots of said transmission signal according to the predetermined hopping pattern.
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Accused Products
Abstract
The present invention relates to a method and system for transmitting in a wireless communication system, a transmission signal divided into at least two signal parts by using transmission beams of at least two subarrays (SA1, SA2) of an antenna array. The transmission beam of at least one of the at least two subarrays (SA1, SA2) is at least in part controlled based on a feedback information received from the receiving means (20). Thus, several beams are generated using an antenna array with more than two antennas, wherein an open-loop diversity is used to split the transmission between the beams, and a closed-loop feedback-based diversity is used to optimize the beams, as well as possibly the division of power between the beams. Thereby, the amount of feedback can be controlled so as to achieve significant feedback gain in a multi-antenna transmission even with non-maximal amounts of feedback.
75 Citations
31 Claims
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1. A method for transmitting a transmission signal via an antenna array to a receiving unit of a wireless communication system, comprising:
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dividing said transmission signal into at least two signal parts; transmitting said at least two signal parts by using transmission beams of at least two subarrays of said antenna array; controlling the transmission beams of at least one of said two subarrays at least in part based on feedback information received from said receiving unit; detecting channel characteristics of a transmission channel; and changing a predetermined hopping pattern based on the detected channel characteristics of the transmission channel; wherein said feedback information is generated based on a channel measurement using pilot channels of predetermined antenna elements of at least one of said at least two subarrays, a number of predetermined antenna elements being smaller than a total number of the antenna elements, and the receiving unit measuring the channels of all antenna elements of the antenna array based on channel measurements using only the pilot channels of the predetermined antenna elements; and wherein at least one of said predetermined antenna elements changes between slots of said transmission signal according to the predetermined hopping pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for transmitting a transmission signal via an antenna array to a receiving unit of a wireless communication system, comprising:
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a dividing unit for dividing said transmission signal into at least two signal parts; a transmitting unit for transmitting said at least two signal parts by using transmission beams of at least two subarrays of said antenna array; a control unit for controlling the transmission beam of at least one of said at least two subarrays at least in part based on feedback information received from said receiving unit; and a pilot control unit for changing at least one of said predetermined antenna elements between slots of said transmission signal according to a predetermined hopping pattern which is changed based on detected channel characteristics of a channel; wherein said system is configured to generate said feedback information based on a channel measurement using pilot channels of predetermined antenna elements of at least one of said at least two subarrays, a number of predetermined antenna elements is smaller than a total number of the antenna elements, and the receiving unit measures the channels of all antenna elements of the antenna array based on channel measurements using only the pilot channels of the predetermined antenna elements. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A network device for transmitting a signal via an antenna array to a mobile terminal, said network device comprising:
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a dividing unit for dividing said transmission signal into at least two signal parts; a transmitting unit for transmitting said at least two signal parts by using transmission beams of at least two subarrays of said antenna array; a control unit for controlling the transmission beam of at least one of said at least two subarrays at least in part based on feedback information received from said mobile terminal; and a pilot control unit for changing at least one of said predetermined antenna elements between slots of said transmission signal according to a predetermined hopping pattern which is changed based on detected channel characteristics of a channel; wherein said network device is configured to receive generated feedback information which is based on a channel measurement using pilot channels of predetermined antenna elements of at least one of said at least two subarrays, a number of predetermined antenna elements is smaller than a total number of the antenna elements, and the receiving unit measures the channels of all antenna elements of the antenna array based on channel measurements using only the pilot channels of the predetermined antenna elements. - View Dependent Claims (29)
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30. A terminal device for receiving a transmitted signal from a network device, comprising:
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a downlink signal pilot extraction unit for extracting or filtering pilot signals transmitted by predetermined antenna elements of at least two subarrays via pilot channels; a channel estimation unit for performing a channel estimation based on the extracted pilot signals; a quantization unit for receiving the channel estimation and generating quantized feedback information for transmission to the network device; a transceiver unit for transmitting the generated feedback information to the network device; and a space time transmit diversity decoder (STTD) unit for decoding at least two signal parts transmitted from the network element based on an STTD decoding scheme; wherein said feedback information is generated based on a channel measurement using said pilot channels of the predetermined antenna elements of at least one of said at least two subarrays, a number of predetermined antenna elements is smaller than a total number of the antenna elements, and the receiving unit measures the channels of all antenna elements of the antenna array based on channel measurements using only the pilot channels of the predetermined antenna elements; and wherein at least one of said predetermined antenna elements changes between slots of said transmitted signal according to a predetermined hopping pattern which is changed based on detected channel characteristics of a transmission channel. - View Dependent Claims (31)
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Specification