Example communication systems and methods are described. In one implementation, a method receives a first chaotic sequence of a first temporal length, and a second chaotic sequence of a second temporal length. The method also receives a data symbol for communication to a destination. Based on the data symbol, the second chaotic sequence is temporally shifted and combined with the first chaotic sequence to generate a composite chaotic sequence. The first chaotic sequence functions as a reference chaotic sequence while the second chaotic sequence functions as a data-carrying auxiliary chaotic sequence.

A multi-carrier cellular wireless network (400) employs base stations (404) that transmit two different groups of pilot subcarriers: (1) cell-specific pilot subcarriers, which are used by a receiver to extract information unique to each individual cell (402), and (2) common pilots subcarriers, which are designed to possess a set of characteristics common to all the base stations (404) of the system. The design criteria and transmission formats of the cell-specific and common pilot subcarriers are specified to enable a receiver to perform different system functions. The methods and processes can be extended to other systems, such as those with multiple antennas in an individual sector and those where some subcarriers bear common network/system information.

A multi-carrier cellular wireless network (400) employs base stations (404) that transmit two different groups of pilot subcarriers: (1) cell-specific pilot subcarriers, which are used by a receiver to extract information unique to each individual cell (402), and (2) common pilots subcarriers, which are designed to possess a set of characteristics common to all the base stations (404) of the system. The design criteria and transmission formats of the cell-specific and common pilot subcarriers are specified to enable a receiver to perform different system functions. The methods and processes can be extended to other systems, such as those with multiple antennas in an individual sector and those where some subcarriers bear common network/system information.

The Radiofrequency Identification and Location System represents a novel system and method for locating a Remote Transceiver by means of a Tracking Transceiver whereby the Tracking Transceiver transmits its identification (ID) to the Remote Transceiver which responds with its own ID. The IDs consist of unique PN code sequences which alternately can be PN cover codes and orthogonal codes. A Remote Transceiver can respond to multiple Tracking Transceivers simultaneously while a Tracking Transceiver can receive from multiple Remote Transceivers. By measuring the transit time of its transmitted PN code with respect to the PN code received from a Remote Transceiver, the Tracking Transceiver can measure the distance to that Remote Transceiver and home in gradually.

In a wireless network, a primary synchronization signal and a secondary synchronization signal are sent at a predetermined bandwidth in a transmission. The predetermined bandwidth is a lowest operating bandwidth of the wireless network. Data is also sent in the transmission using an operating bandwidth greater than the lowest operating bandwidth.

In a wireless network, a primary synchronization signal and a secondary synchronization signal are sent at a predetermined bandwidth in a transmission. The predetermined bandwidth is a lowest operating bandwidth of the wireless network. Data is also sent in the transmission using an operating bandwidth greater than the lowest operating bandwidth.

Generally discussed herein are systems, devices, and methods for waveform watermarking. A device can include an overt symbol modulator to receive mapped overt data and provide overt data modulated in accord with an overt data modulation scheme, a covert symbol modulator to receive mapped covert data and provide, using dither modulation and micro-amplitude modulation, covert data modulated in accord with a covert data modulation scheme, a switch to receive the modulated covert data and the modulated overt data and forward the covert data and modulated overt data based on a signal indicating whether covert data is to be transmitted or covert data is to be transmitted, and transmission circuitry to produce an electromagnetic waveform of the modulated data from the switch.

A system providing a spread spectrum and a narrowband data transmission may comprise a DSSS transmitter and a DSSS receiver. The DSSS transmitter may convert a bit succession (d.sub.i) into a chip succession (s.sub.k) using a chip sequence (c.sub.j, c.sub.j′) and send a succession of impulses (s(t)) corresponding to the chip succession (s.sub.k). The DSSS receiver may receive impulses (s(t)) sent by the transmitter and filter the received impulses (r(t)) using a filter having an impulse response (x(t)) dependent on the chip sequence (c.sub.j, c.sub.j′). The chip sequence (c.sub.j) may be a spread sequence. The narrowband data transmission may use chip sequence (c.sub.j′) and a corresponding impulse response (x(t)) of the filter. The chip sequence (c.sub.j′) does not comprise a succession having two directly successive arithmetic sign changes and an arithmetic sign change does not occur after the first and before the last chip in the chip sequence (c.sub.j′).

A system providing a spread spectrum and a narrowband data transmission may comprise a DSSS transmitter and a DSSS receiver. The DSSS transmitter may convert a bit succession (d.sub.i) into a chip succession (s.sub.k) using a chip sequence (c.sub.j, c.sub.j′) and send a succession of impulses (s(t)) corresponding to the chip succession (s.sub.k). The DSSS receiver may receive impulses (s(t)) sent by the transmitter and filter the received impulses (r(t)) using a filter having an impulse response (x(t)) dependent on the chip sequence (c.sub.j, c.sub.j′). The chip sequence (c.sub.j) may be a spread sequence. The narrowband data transmission may use chip sequence (c.sub.j′) and a corresponding impulse response (x(t)) of the filter. The chip sequence (c.sub.j′) does not comprise a succession having two directly successive arithmetic sign changes and an arithmetic sign change does not occur after the first and before the last chip in the chip sequence (c.sub.j′).

Provided is a method of blindly estimating WCDMA OVSF of a signal analyzer, which includes: (a) setting SF to 512 and an index thereof to 0; (b) calculating a power average value of a symbol obtained by despreading descrambled data with an OVSF code set by increasing the index from ‘0’ by ‘1’; (c) determining an OVSF code by which the power average value is equal to or greater than a power reference value as a used OVSF code candidate and determining an OVSF code by which the power average value is less than the power reference value as an unused OVSF code; (d) comparing a zero crossing rate of a symbol with a reference value to determine whether the OVSF code candidate is the used OVSF code; and (e) repeating (b) to (d) while reducing the SF half by half until the SF is equal to 4.