A concurrent multistandard detection receiver with prepacket transmission detection capabilities is disclosed. In one aspect, a receiver is configured to switch between two different wireless protocols, alternately listening for incoming messages on one then the other protocol. For at least one listening period, the receiver uses two pretransmission detectors that are configured to detect predictable pretransmission emissions. A third detector may detect traditional transmissions. On detection of a signal that matches a predictable pretransmission emission or a traditional transmission, the receiver confirms that an incoming signal according to that standard is being received and acts in accordance with that signal. If no such emission or transmission was received, or if after trying to confirm the presence of an incoming signal fails, the receiver switches back to listening according to the other protocol.

A concurrent multistandard detection receiver with prepacket transmission detection capabilities is disclosed. In one aspect, a receiver is configured to switch between two different wireless protocols, alternately listening for incoming messages on one then the other protocol. For at least one listening period, the receiver uses two pretransmission detectors that are configured to detect predictable pretransmission emissions. A third detector may detect traditional transmissions. On detection of a signal that matches a predictable pretransmission emission or a traditional transmission, the receiver confirms that an incoming signal according to that standard is being received and acts in accordance with that signal. If no such emission or transmission was received, or if after trying to confirm the presence of an incoming signal fails, the receiver switches back to listening according to the other protocol.

A receiver concurrently demodulates data transmitted with a plurality of protocols. The receiver utilizes multiple and simultaneous protocol detections at preamble and/or packet payload phases. To provide robust detection and achieve fewer false detections, the receiver extends the cross correlation length once a short cross-correlation is valid. The receiver includes a first demodulator path and a second demodulator path with different filter bandwidths. The second demodulator path includes a decimator that reduces data by two. A correlator bank is coupled to the first and second demodulator paths and concurrently detects preamble symbols associated with a plurality of protocols. A first noise detector is coupled to the first demodulator path and a second noise detector is coupled to the second demodulator path. A first symbol identifier circuit is coupled to the first demodulator path and a second symbol identifier circuit coupled to the second demodulator path to provide packet payload symbol detection.

An apparatus includes a radio frequency (RF) receiver to receive packets. The RF receiver includes first and second synchronization field detectors (SFDs). The first and second SFDs detect synchronization headers generated using first and second physical layer (PHY) modes, respectively.

A synchronization timing detector includes n correlators, a calculation unit, and a symbol timing estimating unit. The n correlators calculate and output correlation values, between a received signal oversampled m times for one symbol period and a known synchronization pattern, by shifting sample timings by m/n samples each, where m is a natural number, and n is a natural number that satisfies 3≤n≤m and is a divisor of m. The calculation unit generates n correlation value vectors by arranging the correlation values output from the n correlators on polar coordinates at intervals of an angle of 2π(n/m) radians, and adds the n correlation value vectors to calculate an angle of a resultant vector of the correlation value vectors. The symbol timing estimating unit estimates a symbol timing of the received signal based on the angle of the resultant vector calculated by the calculation unit.

A method for estimating a time-of-arrival of a packet received by a receiver includes storing a reference bit-pattern and receiving a plurality of samples in a samples-buffer. In a bit-pattern detector, a matching group of samples having a bit-pattern which matches the reference bit-pattern is identified. In a correlator, a group of three correlation values is determined from the matching group of samples, including a local maximum correlation value, P0, an immediately preceding correlation value, Pm, and an immediately succeeding correlation value Pp. In an estimation unit, a polynomial function f(δ) of the difference, δ, between Pm and Pp is used to estimate a timing offset T.sub.frac, between the local maximum correlation value and a correlation peak. The time-of-arrival is estimated from a time of the local maximum correlation value P0, and T.sub.frac.

A wideband chaotic waveform that is rateless in that it may be modulated at virtually any rate and has a minimum of features introduced into the waveform. Further, the waveform provided may be operated below a signal to noise ratio wall to further enhance the LPD and LPE aspects, thereof. Additionally, the present disclosure may provide a mix of coherent and non-coherent processing techniques applied to signal samples to efficiently achieve coarse synchronization with a waveform that is faster, more efficient and more accurate than using time domain signal correlators alone.

Communication systems and methods in accordance with various embodiments of the invention utilize modulation on zeros. Carrier frequency offsets (CFO) can result in an unknown rotation of all zeros of a received signal's z-transform. Therefore, a binary MOCZ scheme (BMOCZ) can be utilized in which the modulated binary data is encoded using a cycling register code (e.g. CPC or ACPC), enabling receivers to determine cyclic shifts in the BMOCZ symbol resulting from a CFO. Receivers in accordance with several embodiments of the invention include decoders capable of decoding information bits from received discrete-time baseband signals by: estimating a timing offset for the received signal; determining a plurality of zeros of a z-transform of the received symbol; identifying zeros from the plurality of zeros that encode received bits by correcting fractional rotations resulting from the CFO; and decoding information bits based upon the received bits using a cycling register code.

A concurrent multistandard detection receiver with prepacket transmission detection capabilities is disclosed. In one aspect, a receiver is configured to switch between two different wireless protocols, alternately listening for incoming messages on one then the other protocol. For at least one listening period, the receiver uses two pretransmission detectors that are configured to detect predictable pretransmission emissions. A third detector may detect traditional transmissions. On detection of a signal that matches a predictable pretransmission emission or a traditional transmission, the receiver confirms that an incoming signal according to that standard is being received and acts in accordance with that signal. If no such emission or transmission was received, or if after trying to confirm the presence of an incoming signal fails, the receiver switches back to listening according to the other protocol.

A radio apparatus correlates signal data with stored synchronization data to determine correlation data. The signal data represents a received radio-frequency signal that encodes a data frame, which has a synchronization preamble with a plurality of instances of a predetermined synchronization sequence. The stored synchronization data represents the predetermined synchronization sequence. The radio apparatus identifies a set of peaks in the correlation data, and uses a timing criterion to identify a plurality of subsets of the set of peaks, such that time values of the peaks of each identified subset satisfy the timing criterion. The radio apparatus calculates a correlation score C.sub.j for each of the identified subsets from correlation values of the subset's peaks, and uses the correlation scores C.sub.j to select a subset from the plurality of subsets. Timing or frequency synchronization information for the radio apparatus is determined from the peaks of the selected subset.