摘要:
A digital communication system includes a generator for generating a plurality of pulse trains, each having a different timing, and pre-compensation circuitry for synchronizing the plurality of pulse trains to a timing signal. The system also includes comparison circuitry for simultaneously comparing a received burst code signal to each of the plurality of pulse trains, where the burst code signal is synchronized to the timing signal, and a detector for detecting which of the pulse trains is a closest temporal match to the burst code signal. The pre-compensation circuitry operates to reduce acquisition time and keep PN code uncertainties within the range of the comparison circuitry.
摘要:
A method and system for managing Priority Messages in a hybrid TDMA-Spread Spectrum (TDMA-SS) communication system is provided. The method and system include a HUB for generating a HUB TDMA epoch, wherein the HUB TDMA epoch includes at least one Priority Message (PM) slot. The PM slot includes a plurality of assignable PM sub-slots. The method and system also include at least one SPOKE, wherein the at least one SPOKE is adapted to transmit a Priority Message during its assigned PM sub-slot within the HUB TDMA epoch.
摘要:
A method is disclosed for PN correlation and symbol synchronization of a spread spectrum signal at a receiver when a symbol boundary of the spread spectrum signal is not on a PN epoch or is otherwise unknown. The method includes the operation of modulating the spread spectrum signal with a PN code to form a potentially despread signal. The potentially despread signal can be integrated for a plurality of symbol times at a rate of N integrations per symbol time to form N symbol energies per symbol for a plurality of symbols. Each of the N symbol energies can correspond to a different symbol time hypothesis. The N symbol energies from the plurality of symbols can be added respectively to form N summed symbol time hypotheses. The Nth summed symbol time hypothesis having maximum power can be found. The Nth summed symbol time hypothesis can relate to a location of the symbol boundary.
摘要:
A system and method for using Psuedo-Noise (PN) phase to determine frame start of a data frame is provided. The system and method includes at least two PN component codes, wherein the at least two PN component codes are relatively prime. A received PN composite encoded signal is correlated with at least one of the PN component codes and a frame start is determined. With reference to frame start at least one training sequence bit is located. The training bits may be overwritten on FEC encoded frame data such that a FEC decoder may be used to recover data overwritten by the training sequence bit(s).
摘要:
In one exemplary embodiment, an antenna arrangement includes: a substrate; and a plurality of dipole antenna elements disposed on the substrate, wherein the plurality of dipole antenna elements are randomly-oriented with respect to each other. In further exemplary embodiments, the plurality of dipole antenna elements includes at least six dipoles that are all electrically fed and do not need to be magnetically fed in order to generate and detect an arbitrary polarization. In still further exemplary embodiments, each dipole element has a fractal shape.
摘要:
Communication of data over a multiple-input multiple-output (MIMO) channel includes allocating transmission power unequally to the different data streams. The transmission power allocation is performed without regard to a state of a changing channel response of the MIMO channel. A relatively low complexity interference cancelling receiver can therefore decode the data streams.
摘要:
Wireless terminals, systems, and methods use interlaced diplexers. A first diplexer can provide a first pair of bands separated by a first separation band, and a second diplexer can provide a second pair of bands separated by a second separation band. The first separation band and the second separation band can overlap. Transceivers (comprising transmitters and receivers) can be coupled to the diplexers to provide frequency-division duplex communications using one or both of the pairs of bands.
摘要:
A receiver (20) for performing timing recovery over at least one complex channel at low or less than zero SNR (signal power to noise power, in dB) has at least one receive element such as an antenna, an analog-to-digital converter 21 (ADC), a fractional interpolation filter 23, a matched filter 24, and a timing correction loop 26. The timing correction loop 26 selects a minimum mean square error from the output of the matched filter 24 to determine a timing signal output to the interpolation filter 23, and provides one-bit weights to the matched filter 24. Preferably, the timing correction loop 26 includes a magnitude detector 26c, a moving average filter 26b, and a timing error detector 26a that outputs an integer m and fractional μ timing factor to the interpolation filter 23. Within a phase correction loop 27 is a maximum likelihood channel estimator 27b and a phase error detector 27a that controls a phase rotator 22 disposed between the ADC 21 and the interpolation filter 23.