Abstract:
A method for cooperative relaying within multi hop wireless communication systems includes a base station, in an attempt to decode a data packet, combining hard sliced channel bits and Logarithmic Likelihood Ratio (LLR) quality information received from relay stations who had also received the data packet with stored information about the data packet.
Abstract:
A method and system for link adaptation between a wireless multi-carrier access point (102) and a wireless multi-carrier communication device (104) is described. The wireless multi-carrier access point obtains a set of available LEP methods from the wireless multi-carrier communication device. The wireless multi-carrier access point selects an LEP method from the set of available LEP methods, based on at least one link parameter. The wireless multi-carrier access point then communicates the LEP method selected, to the wireless multi-carrier communication device. The selected LEP method is used during the transmission of information between the wireless multi-carrier access point and the wireless multi-carrier communication device.
Abstract:
An Orthogonal Frequency Division Multiplexing, OFDM, transmitter comprises a signalling data generator (113) which generates a set of data symbols indicative of physical layer characteristics of data transmissions from the OFDM transmitter (100). A first symbol generator (115) and second symbol generator (117) generates a first and second OFDM signalling symbol by allocating the set of data symbols to subcarriers. The allocation of the physical layer data symbols to subcarriers is different for the first OFDM signalling symbol and the second OFDM signalling symbol. A data packet generator (105) and transmitter (101) generate a data packet and transmit this to an OFDM receiver (300). The OFDM receiver (300) determines the physical layer data symbols by combining the data symbols of corresponding subcarriers of the first and second OFDM signalling symbols and uses the resulting information to decode the user data of the data packet.
Abstract:
A transmitter comprises a block generator (109) which divides a data symbol stream into data symbol blocks. A divide processor (111) divides each block into a first set of data symbols stored in a first set buffer (113) and a second set of data symbols stored in a second set buffer (115). A space time block encoder (117) codes the first set in accordance with a space time block code to generate a coded set of data symbols. A parallel processor (119) then creates a plurality of parallel data streams from the coded set and the second set. Each of the parallel data streams is allocated to one of a plurality of antennas (129-135). A plurality of parallel stream transmitters (121-127) transmits the parallel data streams in parallel in a communication channel from the plurality of transmit antennas (129-135).
Abstract:
A receiver for an orthogonal frequency division multiplex radio signal in which a carrier frequency is modulated by sub-carrier signals (S1) coded with data. Analogue signal processing means (3 to 12) produces base-band analogue signals (I-Rx, Q-Rx) in phase quadrature and analogue-to-digital converters (13, 14) convert the analogue signals to phase quadrature digital signals (xI(n), xq(n)). The digital signal processor includes the OFDM demodulator (15) and mismatch compensation (17, 18). The mismatch compensation (17, 18) combines each of the reproduced sub-carrier signals (RI) with a limited number of the reproduced sub-carrier signals (RI-Rk) according to respective frequency offset coefficient (I, k) that is a function of an estimated value of the offset (fc) of the reference frequency relative to the carrier frequency.
Abstract:
Apparatus for estimating carrier and clock frequency offsets in OFDM systems employs a maximun likelihood estimator operation on the demodulated signals. The invention has the benefit of low complexity and obviates the need for any requirement for a dedicated training channel.
Abstract:
An Orthogonal Frequency Division Multiplexing, OFDM, transmitter comprises a signalling data generator (113) which generates a set of data symbols indicative of physical layer characteristics of data transmissions from the OFDM transmitter (100). A first symbol generator (115) and second symbol generator (117) generates a first and second OFDM signalling symbol by allocating the set of data symbols to subcarriers. The allocation of the physical layer data symbols to subcarriers is different for the first OFDM signalling symbol and the second OFDM signalling symbol. A data packet generator (105) and transmitter (101) generate a data packet and transmit this to an OFDM receiver (300). The OFDM receiver (300) determines the physical layer data symbols by combining the data symbols of corresponding subcarriers of the first and second OFDM signalling symbols and uses the resulting information to decode the user data of the data packet.
Abstract:
A method for cooperative relaying within multi hop wireless communication systems includes a base station, in an attempt to decode a data packet, combining hard sliced channel bits and Logarithmic Likelihood Ratio (LLR) quality information received from relay stations who had also received the data packet with stored information about the data packet.
Abstract:
A transmitter comprises a block generator (109) which divides a data symbol stream into data symbol blocks. A divide processor (111) divides each block into a first set of data symbols stored in a first set buffer (113) and a second set of data symbols stored in a second set buffer (115). A space time block encoder (117) codes the first set in accordance with a space time block code to generate a coded set of data symbols. A parallel processor (119) then creates a plurality of parallel data streams from the coded set and the second set. Each of the parallel data streams is allocated to one of a plurality of antennas (129-135). A plurality of parallel stream transmitters (121-127) transmits the parallel data streams in parallel in a communication channel from the plurality of transmit antennas (129-135).
Abstract:
A method and system for link adaptation between a wireless multi-carrier access point (102) and a wireless multi-carrier communication device (104) is described. The wireless multi-carrier access point obtains a set of available LEP methods from the wireless multi-carrier communication device. The wireless multi-carrier access point selects an LEP method from the set of available LEP methods, based on at least one link parameter. The wireless multi-carrier access point then communicates the LEP method selected, to the wireless multi-carrier communication device. The selected LEP method is used during the transmission of information between the wireless multi-carrier access point and the wireless multi-carrier communication device.