公开(公告)号：EP1779548A1

公开(公告)日：2007-05-02

申请号：EP05776673.5

申请日：2005-08-04

申请人： Nokia Corporation

发明人： MUKKAVILLI, Krishna, Kiran ,  SABHARWAL, Ashutosh ,  AAZHANG, Behnaam

IPC分类号： H04B7/04 ,  H04L1/12

CPC分类号： H04B7/0417 ,  H04B7/043 ,  H04B7/0443 ,  H04B7/0634 ,  H04B7/0639 ,  H04B7/0663

摘要： The telecommunications system described herein implements a multi-rank beamformer for use in wireless systems equipped with multiple transmit and multiple receive antennas. The multi-rank beamformer uses finite-rate feedback of channel conditions to achieves close to theoretical performance indicated by the water-filling algorithm, while avoiding the computational complexity associated with space time codes. In addition, the multi-rank beamforming system described herein improves on the performance of unit rank beamforming methods by maintaining the gains over space time codes over a broader range of transmission rates.

公开(公告)号：EP1629620A2

公开(公告)日：2006-03-01

申请号：EP04733043.6

申请日：2004-05-14

申请人： Nokia Corporation

发明人： BORRAN, Mohammad, Jaber ,  SABHARWAL, Ashutosh ,  AAZHANG, Behnaam ,  VARSHNEY, Prabodh

IPC分类号： H04L1/02

CPC分类号： H04L25/0202 ,  H04L1/0612 ,  H04L27/3427

摘要： A signal constellation (50) for a multiple input/multiple output (MIMO communication system (20) when channel knowledge at the receiver is imperfect includes at least two (n-1)-dimensional sub-constellations of points that together form an n­dimensional constellation (50), the number n representing real dimensions and n=2M where M is the number of transmit antennas (26). The n-dimensional spherical constellation (50) may define a single sphere or a plurality of concentric subset spheres, and points between subsets are separated by a Kullback-Leibler distance rather than a Euclidian distance. Each sphere has sub-constellations that preferably are arranged in symmetric pairs that define equal numbers of points that lie in parallel planes, to allow recursive construction that minimizes computational complexity. An appropriate constellation may be chosen by ceasing a search once the optimum distance stops increasing as a number of the concentric levels increases.

公开(公告)号：EP2047612A2

公开(公告)日：2009-04-15

申请号：EP07734776.3

申请日：2007-06-06

申请人： Nokia Corporation

发明人： CHAKRABARTI, Arnab ,  DE BAYNAST, Alexandre ,  SABHARWAL, Ashutosh ,  AAZHANG, Behnaam

IPC分类号： H04B7/15 ,  H04L25/20

CPC分类号： H04L1/0045 ,  H04B7/155 ,  H04B7/2606 ,  H04L2001/0097

摘要： A method including transmitting a binary vector from a source node to a relay node and receiving a signal vector at the relay node. The method also includes compressing the signal at the relay node by multiplying the signal with a matrix using probabilities and converting output probabilities from the multiplying into retransmission signal amplitudes, the signal amplitude depending not only on a probability of a bit but on a transmission power constraint at the relay node. The method also includes transmitting, by the relay node, estimates of information from the source node to a destination node.

公开(公告)号：EP1743437A2

公开(公告)日：2007-01-17

申请号：EP05731524.4

申请日：2005-03-29

申请人： Nokia Corporation

发明人： AHMED, Nasir ,  KHOJASTEPUR, Mohammad, Ali ,  SABHARWAL, Ashutosh ,  AAZHANG, Behanaam

IPC分类号： H04B7/00

CPC分类号： H04W52/42 ,  H04W24/00 ,  H04W88/04

摘要： A method for reducing outages in a cooperative network comprising measuring a channel gain for each of a plurality of received signals one of the received signals comprising a source signal, executing an algorithm utilizing the channel gain of the source signal and at least one other of the plurality of channel gains to determine a source transmit power value, and transmitting the source transmit power value to the source.

公开(公告)号：EP1568155A2

公开(公告)日：2005-08-31

申请号：EP03783078.3

申请日：2003-10-29

申请人： Nokia Corporation

发明人： MUKKAVILLI, Krishna Kiran ,  SABHARWAL, Ashutosh ,  AAZHANG, Behnaam

IPC分类号： H04B7/14 ,  H04B1/02 ,  H04B7/02

CPC分类号： H04B7/0639 ,  H01Q21/00 ,  H04B7/0443 ,  H04B7/0617 ,  H04B7/0669 ,  H04W52/42

摘要： Beamforming systems having a few bits of channel state information fed back to the transmitter benefit from low complexity decoding structures and performances gains compared with systems that do not have channel state feedback. Both unit rank and higher rank systems are implemented. Substantial design effort may be avoided by following a method of using functions formulated for space-time systems with the change that the channel coherence time is equated to the number of transmit antennas and the number of antennas in the space-time formulation is fixed at one.