摘要:
A method for generating a signal is presented. The method includes selecting a first set of carrier frequencies that are integral multiples of a first frequency interval, and selecting a second set of carrier frequencies that are integral multiples of a second frequency interval. The second frequency interval is an integral multiple of the first frequency interval and the second set is a subset of the first set. The method includes, for each of one or more signal carrier frequencies in the second set, selecting a plurality of associated carrier frequencies in the first set including a peak carrier frequency having substantially the same value as the signal carrier frequency, and modulating waveform frequency components at each of the selected plurality of associated carrier frequencies according to the same data value.
摘要:
Methods and systems are operable to aggregate data. A plurality of data units can be received. The data units can be combined based upon a class associated with the data and a next hop associated with the data. A link can be provided for the combined data units based on service quality requirements for the traffic class associated with the class.
摘要:
Communicating among stations in a network includes providing repeated beacon transmissions from at least some of the stations including a first station. The first station is assigned to a first level. Any stations that can reliably receive transmissions from the first station are assigned to a second level. Any stations not assigned to any of the preceding levels that can reliably receive transmissions from the preceding level are assigned to each of one or more higher levels. Timing information at each station in a given level is synchronized according to transmissions received from at least one station in the preceding level.
摘要:
An access contention scheme having both multi-level priorities and a contention-free access indicator for use by a station in a network of stations. When a contention control indicator is detected for a contention period, a station having a frame to transmit determines from the contention control indicator if it is permitted to contend for access to the transmission medium during the contention period. The station determines if the contention control indicator indicates a contention-free access and, if the contention control information indicates a contention-free access, the station determines if a channel access priority level associated with the frame to be transmitted is higher than a channel access priority level associated with a last transmitted frame. If the channel access priority level associated with the frame to be transmitted is higher, the station detects whether any station in the network of stations intends to contend for access to the medium at a channel access priority level that is higher than the channel access priority level associated with the frame to be transmitted. If so, the station defers contention for access. Each station listens for channel access priority levels of other stations and may signal its own channel access priority level during a priority resolution period preceding the contention period. The channel access priority is signaled as a two bit value and the priority resolution period includes two priority resolution slots corresponding to the two bit value and is used to separate higher channel access priority values from lower channel access priority values.
摘要:
A rate-adaptive mechanism for optimizing transmitter/receiver connections on a carrier-by-carrier basis for maximum date rate based on channel attributes for that connection and direction. Channel information is produced by a channel adaptation process based on channel characteristics and is stored in both transmitter and receiver as a channel map with an associated a channel map index for channel map look-up. The channel map index for a channel map used to modulate a payload of a frame is conveyed by transmitter to receiver in the frame so that the receiver is able to select the correct channel map for demodulation.
摘要:
A robust Media Access Control (MAC) scheme for network stations operating in an OFDM transmissions network. The MAC scheme uses robustly transmitted frame control information to ensure network synchronization (for media access) and convey channel access prioritization for QoS. Frame control information can occur in a frame before and after the frame's payload, or in a response.
摘要:
An encoder/decoder scheme for robust transmission of PHY layer frame control information (to support medium access) in OFDM frames (or packets). The PHY layer frame control information to be modulated onto carriers in OFDM symbols is encoded using a product coding to form a product code block or matrix. The product coding is based on a shortened hamming code codeword set having properties of symmetry. Elements of the product code matrix are interleaved so that the elements are modulated onto the carriers of the symbols in diagonal groupings (across time and frequency) and with some degree of redundancy. The modulated elements are demodulated to produce soft decision values, which are de-interleaved to combine copies of the soft values for elements and re-order the soft values in the order of the elements prior to interleaving. The soft values for each row and each column are provided to a turbo product decoder, which performs a number of iterations of row/column decoding, each iteration applying a weighting to the results to enhance the reliability of the results of each next successive iteration. Upon completion of the final iteration, the decoder applies a hard decision to the soft values to produce a set of hard values for each of the soft values that corresponds to the frame control information. Given the symmetry of the code set, the row/column decoding generates a complete set of correlation values from only a subset of the complete set of correlation values and uses a reduced number of MAP decoding operations to select the best correlation values for each of the soft values.
摘要:
A method is described for temporally aligning a received symbol that is transmitted via orthogonal channels, e.g., OFDM channels, with a reference symbol and/or an earlier received symbol. The method includes computing phases of the first symbol for the orthogonal transmission channels and comparing the computed phases of the first symbol with phases of the reference. The phases of the first symbol are successively displaced by a predetermined phase shift which depends on the channel frequency to obtain a correlation result. The temporal alignment is determined by detecting a correlation maximum based on the correlation result and used to synchronize the first symbol with the reference. The reference can also be an earlier received symbol to provide autocorrelation. The received symbols can be processed by applying a window function, e.g. a Hanning, Hamming or Blackman window. Phase correlation provides reliable time synchronization in the presence of jammers emitting narrowband signals in excess of 32 dB above the signal level.
摘要:
Network signals are coupled to and from a first communication medium that is coupled to one or more nodes of a first network that exchange signals according to at least one scheduling constraint of the first communication medium. Network signals are coupled to and from a second communication medium that is coupled to one or more nodes of a second network that exchange signals according to a schedule compatible with scheduling information received from the first network. Information conveyed by the coupled network signals is communicated between a first network node and a second network node, according to the schedule compatible with the scheduling information received from the first network.
摘要:
Communicating between stations over a shared medium comprises: receiving, at a destination station, a first waveform that includes one or more segments of a payload that originated from an origin station with a sequence of multiple segments, the one or more segments included in the first waveform having been transmitted over the shared medium by the origin station and by each of one or more repeater stations, and the first waveform indicating which of the sequence of multiple segments were not correctly decoded by at least one of the repeater stations; generating, based on the first waveform, acknowledgement information that specifies which of the sequence of multiple segments have been correctly decoded by the destination station; and transmitting a second waveform from the destination station over the shared medium, the second waveform including the acknowledgement information.