摘要:
A frame structure for communicating over a high-throughput communication channel includes a channelization field as part of a current data unit to indicate a frequency and space configuration of subsequent portions of the current data unit.
摘要:
Methods and apparatus provide increased symbol length with more subcarriers in a fixed-bandwidth system. The subcarriers spacing may be reduced to provide increased symbol length and enable higher throughput. In one implementation, a system compatible with the IEEE P802.11n proposal can use 128 subcarriers in 20 MHz operation to provide increased throughput in lower-bandwidth channel operation.
摘要:
In an orthogonal frequency division multiplexed (OFDM) system, a transmitter and/or receiver communicate separate data streams on non-orthogonal spatial channels. Each spatial channel may use the same set of OFDM subcarriers and may take advantage of the multipath characteristics of the spatial channel allowing the communication of additional data without an increase in frequency bandwidth. Space-frequency subcarrier modulation assignments may be dynamically assigned on a per subcarrier basis as well as a per spatial channel basis to help maximize the data-carrying capacity of the channel. In some embodiments, each of the spatial channels may be associated with one of a plurality of spatially diverse antennas. In other embodiments, beamforming may be performed to allow the transmission and/or reception of signals within the spatial channels.
摘要:
Methods and systems for communicating in a wireless network may distinguish different types of packet structures by modifying the phase of a modulation constellation, such as a binary phase shift keying (BPSK) constellation, in a signal field. Receiving devices may identify the type of packet structure associated with a transmission or whether the signal field is present by the phase of the modulation constellation used for mapping for the signal field. In one embodiment, the phase of the modulation constellation may be determined by examining the energy of the I and Q components after Fast Fourier Transform. Various specific embodiments and variations are also disclosed.
摘要:
Briefly, some embodiments of the invention may provide devices, systems and methods for wireless combined-signal communication. For example, a method in accordance with an embodiment of the invention may include transmitting a combined signal over a combined channel by mapping a first block of said combined signal to be carried by a first sub-channel of said combined channel and mapping a second block, substantially identical to said first block, to be carried by a second sub-channel of said combined channel.
摘要:
Briefly, some embodiments of the invention may provide devices, systems and methods for wireless combined-signal communication. For example, a method in accordance with an embodiment of the invention may include transmitting a combined signal over a combined channel by mapping a first block of said combined signal to be carried by a first sub-channel of said combined channel and mapping a second block, substantially identical to said first block, to be carried by a second sub-channel of said combined channel.
摘要:
Methods, apparatus and systems are disclosed for block encoding/decoding information wireless networks having narrow decoding latency restrictions. A method includes identifying a length of information to be sent in a block code and encoding the information to be sent in the block code into one or more codewords, where the number of codewords and the amount of information encoded within each codeword is adjusted based on the identified length and to achieve a similar codeword error probability for each codeword considering available decoding time for decoding a last codeword is less than available decoding time for decoding a first codeword. In certain implementations low density parity check (LDPC) encoding may be used in combination with OFDM to provide reliable communications in a high throughput WLAN.
摘要:
In a multiple-input multiple-output (MIMO) system, multiple receive antennas produce a received signal vector, Y, which includes an element for each of the receive antennas. In an embodiment of a de-mapping method performed within a MIMO receiver, a quadrature phase shift keying (QPSK) search is performed within a search space that includes the full constellation of symbol points. Based on the results of the QPSK search, the search space is reduced to fewer than all of the quadrants, and the received signal vector data is scaled and transformed to the reduced search space. A lower-level QPSK search is performed, and the process is repeated until the modulation order is reduced to a QPSK constellation. Hard or soft decisions corresponding to the search results may then be passed to a decoder.
摘要:
In a communication system using closed loop MIMO, beam forming information may be fed back from a receiver to a transmitter sequentially over a number of frames. The beam forming matrices that are fed back may be quantized.
摘要:
The device assists those who are visually handicapped and, in particular, warns blind or visually impaired travellers that they have entered a potentially dangerous area proximal to the edge of boarding platforms of the type typically found in public railway transit systems. An InfraRed Integrated Information System consists of an array of infrared transmitters and a portable detector/warning device to be held by the blind traveller. The transmitters create a beam of infrared light which bathes the section of the platform proximal to the platform edge. As the traveller moves into the region of the platform covered by the emission, the sensors in the warning device are activated and by audio, tactile or other stimuli alert the traveller of entry into the danger zone.