公开(公告)号：EP1913724A2

公开(公告)日：2008-04-23

申请号：EP06795244.0

申请日：2006-08-11

申请人： Nokia Corporation

发明人： IONESCU, Dumitru, Mihai ,  RAGHOTHAMAN, Balaji

IPC分类号： H04L7/00 ,  H04B7/04 ,  H04L25/02

CPC分类号： H04L5/0048 ,  H04B7/04 ,  H04L5/0023 ,  H04L25/0204 ,  H04L25/0226 ,  H04L25/0232 ,  H04L25/03828 ,  H04L27/2604 ,  H04L27/2655 ,  H04L27/2657 ,  H04L27/2662

摘要： A method, system, apparatus and computer program product are provided for placing pilot symbols in an OFDM system using sets of multidimensional points having a structure that is derived from discernible expansions of generalized orthogonal designs. These sets of multidimensional points may be used to form pilot symbols on a two-dimensional frequency-time pilot symbol grid for sampling the flat fading process on various subcarriers of an OFDM MIMO system, transmit antennas, and OFDM symbols. The pilot information associated with the pilot symbols may be used to perform initial carrier synchronization and OFDM symbol timing while discerning between candidate base stations.

公开(公告)号：EP1687924A2

公开(公告)日：2006-08-09

申请号：EP04798862.1

申请日：2004-11-15

申请人： Nokia Corporation

发明人： RAGHOTHAMAN, Balaji ,  ZHANG, Jianzhong

IPC分类号： H04L1/00

CPC分类号： H04B7/0417 ,  H04B7/0443 ,  H04B7/0465 ,  H04B7/0632 ,  H04B7/0669 ,  H04B7/0697 ,  H04L1/0002 ,  H04L1/0007 ,  H04L1/0033 ,  H04L1/0041 ,  H04L1/0065 ,  H04L1/0071 ,  H04L1/06 ,  H04L1/0656

摘要： A method for transmitting a packet of N input bits includes encoding all of the N bits as a single entity, such as with an interleaver of length N within a turbo coder, outputting M encoded bits, channel interleaving the M bits, splitting the M encoded bits into a parallel first and second portion, and transmitting them over separate channels to achieve spatial diversity. The size of the first and second portion is determined based on a closed feedback loop that provides some knowledge of the channel, preferably a measure of channel capacity. The feedback loop may also provide channel knowledge to a subpacket selector associated with each transmit antenna, which determines an appropriate rate for that channel and selects subpackets to fill a transmission packet for that channel. The subpacket selectors choose a subpacket of systematic bits and fill the remaining transmission packet size with subpackets of parity bits. Eigenvectors may be employed to transmit each transmission packet over more than one channel with a power disparity between the channels. A transmitter according to the present invention is also described.

公开(公告)号：EP1504535A1

公开(公告)日：2005-02-09

申请号：EP03728913.9

申请日：2003-05-15

申请人： Nokia Corporation

发明人： RAGHOTHAMAN, Balaji ,  DERRYBERRY, Thomas, R.

IPC分类号： H04B1/38 ,  H04B17/00 ,  H04B1/06 ,  H04B7/00 ,  H04M1/00 ,  H04Q7/20 ,  H01Q3/22 ,  H01Q3/24 ,  H01Q3/26

CPC分类号： H04B7/0634 ,  H04B7/022 ,  H04B7/0641

摘要： Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected (136) by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction (138). A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted (142). The technique is utilized during both non-handoff conditions and during handoff conditions.

公开(公告)号：EP1834456A1

公开(公告)日：2007-09-19

申请号：EP05824099.5

申请日：2005-12-22

申请人： Nokia Corporation

发明人： MANDYAM, Giridhar, D. ,  RAGHOTHAMAN, Balaji ,  DERRYBERRY, Roy, Thomas

IPC分类号： H04L25/02 ,  H04B1/707 ,  H04L27/26

CPC分类号： H04B1/707 ,  H04B2201/70701

摘要： An approach for utilizing a pilot scheme in a spread spectrum communication system (e.g., Multi Carrier Code Division Multiple Access (MC-CDMA)) is provided. A communications link includes a sub-bands and a single pilot channel that is designated for the sub-bands for channel estimation. Pilot symbols transmitted over the single pilot channel are used to determine a first channel estimate associated with a first one of the sub-bands, and a second channel estimate corresponding to a second one of the sub-bands is derived from the first channel estimate.

公开(公告)号：EP1792461A1

公开(公告)日：2007-06-06

申请号：EP05786830.9

申请日：2005-09-08

申请人： Nokia Corporation

发明人： IONESCU, Dumitru, M. ,  RAGHOTHAMAN, Balaji

IPC分类号： H04L27/26 ,  H03M13/29

CPC分类号： H04L1/006 ,  H04B7/0443 ,  H04L1/0003 ,  H04L1/0009 ,  H04L1/0026 ,  H04L1/0066 ,  H04L1/0068 ,  H04L1/0071 ,  H04L1/06 ,  H04L1/0687

摘要： Disclosed is a method to operate a wireless MIMO communication system, where the method includes, for N symbols of a frame of information to be transmitted through a plurality of eigen sub-channels, allocating N1 symbols to a stronger eigen sub-channel and N2 symbols to a weaker eigen sub-channel, where N1 > N2; determining a probability of reception error when transmitting the N2 symbols through the weaker eigen sub-channel for an auxiliary signal-to-noise ratio; solving for a quality of service QoS of the weaker eigen sub-channel and if the QoS is less than a desired QoS, decreasing the value of N and repeating allocating symbols, determining the probability of reception error and solving for the QoS. The symbols maybe systematic symbols output from a turbo coder, and thus replicate the original source bits. In another aspect this invention provides a method to operate a wireless MIMO communication system that includes asymmetrically allocating spreading codes to a stronger eigen sub-channel and to a weaker eigen sub-channel such that the stronger eigen sub-channel is allocated more spreading codes than the weaker eigen sub-channel; and transmitting all systematic bits of turbo coded information over the stronger eigen sub-channel.

公开(公告)号：EP1639842A2

公开(公告)日：2006-03-29

申请号：EP04777330.4

申请日：2004-06-29

申请人： Nokia Corporation

发明人： BOARIU, Adrian ,  RAGHOTHAMAN, Balaji

IPC分类号： H04Q7/20

CPC分类号： H04W52/42 ,  H04W52/281 ,  H04W52/286 ,  H04W52/288 ,  H04W52/343 ,  H04W52/346

摘要： A method for scheduling weighted transmissions from two or more transmit antennas of a base station to each of two or more mobile stations in a closed-loop transmit diversity system, whereby the quantity of power available for data transmission from each transmit antenna is determined and, with respect to each antenna, the power required to transmit data to each mobile station is determined. The number of mobile stations that may be served simultaneously by a base station is determined and, for each combination of respective mobile stations constituting the number of mobile stations that may be served simultaneously, the transmission of data from each transmit antenna to the mobile stations is scheduled to minimize unused power.

摘要翻译： 一种用于从两个调度加权传输或在闭环发射分集系统中，从而可从每一个发射天线的数据发送功率的量确定的开采和多个发射基站到每两个或更多个移动站中的天线的方法， 相对于每个天线，将数据传输到每个移动台所需的功率是确定的开采。 做的移动站的数量可以由基站同时服务是确定性的开采和，用于构成移动台的数量respectivement移动站的每一个组合都可以同时投放，数据从每个发射天线到移动站的传输是 定于减少闲置功耗。

公开(公告)号：EP1997241A2

公开(公告)日：2008-12-03

申请号：EP07751987.4

申请日：2007-03-02

申请人： Nokia Corporation

发明人： NGUYEN, Hoang ,  RAGHOTHAMAN, Balaji

IPC分类号： H04B7/06

CPC分类号： H04B7/0639 ,  H01Q1/246 ,  H01Q3/2605 ,  H04B7/0617 ,  H04B7/0634

摘要： A wireless communication system including receiving and base stations. The receiving station (570) includes a detector (590) that measures a downlink channel correlation matrix for multiple antennas (547) of a base station (500). The detector (590) computes an antenna weight increment vector normal to an antenna weight vector for multiple beams from the multiple antennas (547) of the base station (500). The detector (590) quantizes the antenna weight increment vectors to produce a respective quantized antenna weight increment vector. The receiving station (570) includes a transmitter (580) that sends the quantized antenna weight increment vectors to the base station (500). The base station (500) includes a beamformer selector (565) that receives from the receiving station (570) and re-orthogonalizes the quantized antenna weight increment vector for each of the multiple beams. The base station (500) includes a weight vector modifier (567) that modifies the antenna weight vector for the multiple beams by adding an increment proportional to the respective re-orthogonalized quantized antenna weight increment vector.

公开(公告)号：EP1834421A1

公开(公告)日：2007-09-19

申请号：EP05823030.1

申请日：2005-12-30

申请人： Nokia Corporation

发明人： RAGHOTHAMAN, Balaji ,  ZHANG, Jianzhong ,  WANG, Yan ,  LAMPINEN, Marko

IPC分类号： H04B7/08 ,  H04B7/06

CPC分类号： H04B7/0413 ,  H04B7/0854

摘要： An approach for determining antenna weights in a multiple antenna communication system is provided. The approach jointly optimizes the transmitter weights and the receiver filter. A filter of a receiver (e.g., Linear Minimum Mean Square Error (LMMSE)) is optimized using initial weight values of the transmit antennas. The cost function, which is a mean-squared of a difference between a transmitted signal and an estimated signal, is then modified according to the optimized receiver filter. A transmit filter is then optimized according to the modified cost function. The above approach advantageously can obtain antenna weights when the condition of separability of paths does not exist.

公开(公告)号：EP1766831A1

公开(公告)日：2007-03-28

申请号：EP05761454.7

申请日：2005-07-12

申请人： Nokia Corporation

发明人： ZHANG, Jianzhong ,  RAGHOTHAMAN, Balaji ,  WANG, Yan ,  MANDYAM, Giridhar

IPC分类号： H04L1/00 ,  H04L1/20 ,  H04L1/06

CPC分类号： H04L1/0656 ,  H04B1/7105 ,  H04B1/71055 ,  H04L1/0026 ,  H04L1/20 ,  H04L2025/03426 ,  H04L2025/03617

摘要： In a jointly encoded (JE), spread spectrum communication MIMO system where a demultiplexed packet is transmitted over multiple streams, two versions of a single channel quality indicator (CQI) is disclosed: generalized SNR or constrained mutual information CMI between the transmitted and receives chip vectors. In the receiver, the CMI is constrained so that filtering is suboptimal. The filter bank is preferably LMMSE or MVDR filters that convert the multi-path channel into a single patch channel so that joint sequence detection is unnecessary. Detection is instead by a per-Walsh code architecture, wherein a plurality of Walsh-code specific detectors in parallel detect bits or symbols from the single-channel chips after downconverting chip to symbols. Link to systen t mapping is realizable using the disclosed CQI for a JE MIMO system in that the CQI or related information is returned to the transmitter, which adapts coding rate and/or modulation for the charnel as represented by the CQI.

公开(公告)号：EP1745566A2

公开(公告)日：2007-01-24

申请号：EP05750402.9

申请日：2005-04-19

申请人： Nokia Corporation

发明人： LIU, Ke ,  RAGHOTHAMAN, Balaji ,  ZHANG, Jianzhong

IPC分类号： H04B7/005 ,  H04L1/06

CPC分类号： H04W52/08 ,  H04B7/04 ,  H04W52/24 ,  H04W52/241 ,  H04W52/248 ,  H04W52/54

摘要： Apparatus, and an associated method, for compensating for the effects of fading, or other distortion, in an MIMO communication system. Analysis is made at a receiving station, such as through channel estimation by a channel estimator, of communication conditions on different sub-channels, defined by different communication paths upon which data streams are com­municated to the receiving station from different transmit antenna transducers. Power controllers generate power change requests responsive to the channel estimations. The power change requests are returned to a sending station by way of a feedback channel. And, the power levels at which data is transmitted from different transmit antennas is correspondingly changed.