Induced Incoherency for Joint Transmission
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Accused Products
Abstract
Frequency-selective phase shifts are applied to signals transmitted from multiple transmission points involved in a coordinated (joint) transmission to a given UE. An eNodeB or other network node controlling the joint transmission artificially induces frequency selectivity between signals received by the UE in joint transmission from different transmission points, so as to ensure an even balance between constructive and destructive combination over frequency. By applying frequency-selective phase shifts (e.g., pseudo-random phase shifts) to the different transmission points that perform joint transmission, the signals from the different transmission points are forced to combine at the UE in a non-coherent manner. As a result, uncertainty in how the signals combine is drastically reduced, since it can be expected that the signals will always combine incoherently. The reduced uncertainty translates to reduced back-off offset in the link adaptation, and thus in an increased throughput.
40 Citations
72 Claims
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1-36. -36. (canceled)
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37. A method, performed by one or more fixed nodes in a wireless network, for participating in a coordinated multi-point transmission to a user equipment, the method comprising:
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acquiring channel state information for each of a plurality of transmission points from the user equipment; determining transmission parameters for a joint transmission from the plurality of transmission points to the user equipment, wherein said determining is based on an assumption of non-coherent combining of signals from the plurality of transmission-points at the user equipment; and transmitting data signals from each of the plurality of transmission points to the user equipment, wherein said transmitting comprises applying an induced frequency selectivity to the transmitted data signals from one or more of the transmission points, on a per-transmission-point basis. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A fixed node configured for operation in a wireless network, the fixed node comprising:
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a baseband processor configured to acquire channel state information for each of a plurality of transmission points from the user equipment and to determine transmission parameters for a joint transmission from the plurality of transmission points to the user equipment, wherein said determining is based on an assumption of non-coherent combining of signals from the plurality of transmission points at the user equipment; and one or more transmitter control circuits configured to transmit data signals from each of the plurality of transmission points to the user equipment, wherein said transmitting comprises applying an induced frequency selectivity to the transmitted data signals from at least one of the plurality of transmission points, on a per-transmission-point basis. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56, 57, 58)
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59. A method, in a user equipment, for reporting channel state information, the method comprising:
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measuring a separate channel response for each of two or more reference signals or groups of reference signals; and reporting at least one aggregated channel quality indicator (CQI), based on the measured channel responses and based on an assumption that jointly transmitted signals corresponding to the measured channel responses will, on a per-channel response basis, combine in a non-coherent fashion at the user equipment. - View Dependent Claims (60, 61, 62, 63, 64, 65)
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66. A user equipment configured for operation in a wireless network, the user equipment comprising
a radio circuit configured to receive reference signals, or groups of reference signals, and to transmit channel state information to the wireless network, and a baseband processor configured to: -
measure a separate channel response for each of two or more reference signals or groups of reference signals, and report at least one aggregated channel quality indicator (CQI) using the radio circuit, wherein the at least one aggregated CQI is based on the measured channel responses and is based on an assumption that jointly transmitted signals corresponding to the measured channel responses will, on a per-channel response basis, combine in a non-coherent fashion at the user equipment. - View Dependent Claims (67, 68, 69, 70, 71, 72)
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Specification