摘要:
A magnitude only equalizer equalizes a magnitude of a received wireless signal without regard to phase distortions introduced, and transmits the magnitude equalized signal to a timing recovery loop for improved correlation peak detection in a sync based timing recovery scheme. A channel equalizer receiving the output signal from the timing recovery loop equalizes the signal and corrects any phase distortions introduced by the magnitude only equalizer. The magnitude only equalizer includes at least one filter utilizing only real coefficients and constrained such that the direct term of the overall filter structure within the magnitude only equalizer is unity.
摘要:
A method and associated systems for implementing MIMO communication systems are disclosed. The systems comprise at least one encoder (120a, 120b) for Reed-Solomon encoding a corresponding input data stream of data packets; at least one interleaver (124a, 124b) for interleaving bits of a corresponding encoded input data stream, at least one mapper (128a, 128b) for mapping the interleaved bits of a corresponding encoded input data stream, at least one inverse FFT (132a, 132b) for determining transforms of the mapped interleaved bits of a corresponding encoded bit stream, at least one cyclic prefix unit (136a, 136b) for determining a cyclic prefix of the transformed mapped interleaved bits of a corresponding encoded bit stream; and, at least one pulse shaper (140a, 140b) for shaping pulses of a corresponding encoded bit stream and means for dividing a data stream into a plurality of input data steams, the input data streams associated with a corresponding communication channel. In addition, the method provides a training sequence 700 that imposes minimal overhead on data transmission.
摘要:
A system and method for a simplified Maximum Likelihood (ML) decoding (203) for MIMO systems is provided. The full ML decoding gives the lower bound of the decoding for CC coded MIMO systems. However, the computation cost is too high to be implemented in real system. Many alternative methods have been proposed for the decoding. Among them, weighted Zero Forcing (WZF) is one that can give affordable performance with reasonable computation complexity but there are several dB of performance gap for the WZF decoding and ML decoding. This present invention discloses a decoding system and method having improved performance over WZF decoding with affordable implementation complexity.
摘要:
Disclosed is a system and method for providing backward compatible transmitter diversity in an orthogonal frequency division modulated (OFDM) communication system. According to one aspect of the invention, a method for providing backward compatible transmitter diversity includes the steps of: receiving an input data bit stream; transforming it into an OFDM symbol stream comprised of even and odd symbols; dividing the OFDM symbol stream into a first symbol sub-stream and a second symbol sub-stream; processing the first symbol sub-stream by a first processing block to output a first processed symbol sub-stream; processing the second symbol sub-stream by a second processing block to output a second processed symbol sub-stream; transmitting the first processed symbol sub-stream from a first diversity antenna; and transmitting the second processed symbol sub-stream from a second diversity antenna and both are transmitted over non-overlapping frequencies.
摘要:
A system and method for a simplified Maximum Likelihood (ML) decoding (203) for MIMO systems is provided. The full ML decoding gives the lower bound of the decoding for CC coded MIMO systems. However, the computation cost is too high to be implemented in real system. Many alternative methods have been proposed for the decoding. Among them, weighted Zero Forcing (WZF) is one that can give affordable performance with reasonable computation complexity but there are several dB of performance gap for the WZF decoding and ML decoding. This present invention discloses a decoding system and method having improved performance over WZF decoding with affordable implementation complexity.
摘要:
Multiple input multiple output (MIMO) systems are candidates for higher data rate wireless communication systems. Currently, for a single input single output (SISO) 1802.11a system can provide a transmission data rate up to 54 Mbps. The present invention is a 2 by 2 Multiple In Multiple Out (MIMO) system having a decoding apparatus that increases the data rate to over 100 Mbps but at a computation cost about the same as for optimal decoding for a SISO system and 1/64 of the optimal decoding for a 2 by 2 MIMO system. At a bit error rate (BER) of 10-4 level, the 2 by 2 MIMO system of the present invention provides double the transmission data rate of the SISO system with approximately the same signal to noise ratio (SNR).
摘要:
Bit level, rather than symbol level, diversity combining is employed within a wireless communications receiver. Channel estimates and bit metrics are separately computed for signals received by different antenna elements. Bit metrics are calculated by determining a least squares cumulative difference between all bits within the received symbol and corresponding bits within constellation symbols as modified by the channel estimate. The separately-determined bit metrics are then combined for decoding. Performance improvements over both single antenna systems and multiple antenna systems with symbol level diversity combining are achieved.
摘要:
A first wireless device communicates data to a second wireless device. The first wireless device employs at least one of a first interleaving scheme and a first sub-carrier mapping scheme to produce a first data packet from a first plurality of data bits, and transmits the first data packet to the second wireless device. When the first data packet is not received correctly by the second wireless device, then the first wireless device employs at least one of a second interleaving scheme and a second sub-carrier mapping scheme to create a second data packet from the first plurality of data bits, and transmits the second data packet to the second wireless device.
摘要:
A method (200) for signaling a transmission mode in a wireless communication networks comprises selecting a signature sequence corresponding to the transmission mode of a transmitting device (S210); forming, for each antenna in the transmitting device, a synchronization field based on the selected signature sequence, wherein the synchronization field is included in a preamble (S220); and transmitting, from each antenna in the transmitting device, the data frame that comprises the preamble.
摘要:
A medical system includes one or more MBAN devices which acquire and communicate patient data. One or more medical body area network (MBAN) systems include the one or more MBAN devices communicating the patient data with a hub device via short-range wireless communication. The communication of the patient data via the short-range wireless communication being within a predefined spectrum. The hub device receives patient data communicated from the one or more MBAN devices, communicates with a central monitoring station via a longer range communication and one or more access points (AP), and determines the location of the MBAN system in reference to a healthcare facility. The one or more MBAN devices are inhibited from transmitting within the predefined spectrum when the MBAN hub device is located outside the healthcare facility.