Abstract: A method for conserving bandwidth in a communication system includes spreading a data frame using a first pseudo-noise (PN) spreader. A broadcast frame is spread using a second PN spreader. A complex data stream having a first component and a second component is generated. The data frame is assigned to the first component and the broadcast frame is assigned to the second component. The complex data stream is transmitted to a tag.

Abstract: This disclosure relates to method, device and system for measuring signal quality in a communication system. An access point receives an uplink signal from a transmitter. The uplink signal contains a data portion and a result of a hash function. The uplink signal is received at a time based on a slot start time and a random timing offset and is received while a portion of a second signal is received from a second transmitter. The access point measures a noncoherent energy metric for the uplink signal. The access point computes a local result of the hash function using the data portion. The uplink signal is then discarded if the result of the hash function matches the local result of the hash function but the noncoherent energy metric is below a threshold value.

Abstract: This disclosure relates to method, device and system for detecting errors in a communication system. A signal is received from a transmitter at a receiver wherein the signal includes a data portion and a result of a hash function. The hash function is computed in part from a transmitter identification code. The receiver determines if the result of the hash function matches both the data portion and the transmitter identification code. The receiver discards the signal if the result of the hash function does not match both the data portion and the transmitter identification code of the transmitter.

Abstract: A technique and system is disclosed for controlling power in a spread spectrum system. A fast slot of a frame is received where the frame is divided into a number of fast slots. The received power is measured on the fast slot. A second fast slot is transmitted at a second time with a transmit power setting and a variable spreading factor. The transmit power setting and the variable spreading factor is adjusted based on the received power. The variable spreading factor affects the total number of fast slots that are transmitted.

Abstract: A method for conserving resources in a communication system includes entering an awake state from a sleep state at a first time, where the first time occurs a predetermined period prior to a communication event. The predetermined period is greater than or equal to a worst-case determination period for determining a timing offset relative to an access point. An initial timing offset relative to the access point is determined during the predetermined period. The sleep state is entered for a remainder of the predetermined period upon determination of the initial timing offset. The awake state is entered for the communication event. The timing offset relative to the access point is determined based at least in part on the initial timing offset.

Abstract: A method for communicating through a multiple access communication interface includes receiving a first signal from a first tag, where the first signal is spread using a predetermined pseudo-noise (PN) code, and further where the first signal includes first payload data. A second signal is received from a second tag. The second signal is spread using the predetermined PN code, and the second signal includes second payload data. The first payload data from the first signal is identified at least in part with a PN array despreader. The second payload data from the second signal is also identified at least in part with the PN array despreader.

Abstract: A method of communicating through a random phase multiple access network is provided. A signal that has been spread using a pseudo-noise code and offset by a random timing offset and that contains payload data is received from a device. A destination is selected for the payload data based on a characteristic of the multiple access network. The payload data is transmitted to the selected destination.

Abstract: A method of determining the location of a communication tag in a random phase multiple access communication network is disclosed. A ranging request signal that is spread using a first pseudo-noise code and offset with a first random timing offset is transmitted at a first time. A ranging response signal that is spread using a second pseudo-noise code and offset with a second random timing offset is received at a second time. A propagation delay that is dependent on the first time and the second time is calculated.

Abstract: A method of compensating for doppler phase errors includes receiving a signal at a receiver wherein the signal is spread using a pseudo-noise code, dividing the signal into a plurality of smaller coherent units and then compensating for induced doppler phase errors by analyzing the plurality of smaller coherent units. Analysis may include producing a plurality of coherent sums by summing across the smaller coherent units and then summing non-coherently the plurality of coherent sums. Analysis may also include demodulating a symbol from the smaller coherent units. A modulation technique may be selected from a plurality of modulation techniques and then be used to encode and transmit a symbol stream.

Abstract: A method for conserving bandwidth in a communication system includes spreading a data frame using a first pseudo-noise (PN) spreader. A broadcast frame is spread using a second PN spreader. A complex data stream having a first component and a second component is generated. The data frame is assigned to the first component and the broadcast frame is assigned to the second component. The complex data stream is transmitted to a tag.

Abstract: A method for communicating through a multiple access communication interface includes receiving a first signal from a first tag, where the first signal is spread using a predetermined pseudo-noise (PN) code, and further where the first signal includes first payload data. A second signal is received from a second tag. The second signal is spread using the predetermined PN code, and the second signal includes second payload data. The first payload data from the first signal is identified at least in part with a PN array despreader. The second payload data from the second signal is also identified at least in part with the PN array despreader.

Abstract: A method for de-spreading spread data includes receiving a data stream by multiple access communication where the received data stream is spread using a pseudo-noise (PN) code; multiplying a first portion of the received data stream including data from a first user by a first portion of a PN signal to obtain a first product; providing the first product to a first counter; multiplying a second portion of the received data stream including data from a second user by the first portion of the PN signal to obtain a second product; providing the second product to a second counter; and determining whether the first portion of the PN signal and the second portion of the PN signal produce valid sequences based at least in part on the first product and the second product.

Abstract: A method of establishing communication at a tag includes calculating a metric for each of a plurality of automatic frequency control (AFC) hypotheses where the plurality of AFC hypotheses correspond to a timing used by an access point; based on the calculated metrics, identifying one or more relevant AFC hypotheses; performing a check on a demodulated data stream identified using the one or more relevant AFC hypotheses; identifying a valid AFC hypothesis based at least in part on the check; and determining where a frame starts based at least in part on the check.