Vecima Networks Inc.

Cisco Systems Canada Co.

Other

Ha Hoang Nguyen

Brian Berscheid

Tung Trong Nguyen

Joseph Eric Salt

Eric Salt

Muhammad Hanif

Quang Nguyen

A method is provided for geo-location of a wireless target device. The method is able to generate complete statistical information about the target device in the form of a joint probability density function of the target's location. The method includes obtaining time of arrival measurements associated with reception, at a plurality of receiver devices at known or measured locations, of one or more wireless transmissions made by a target device at a location that is unknown. Based on the time of arrival measurements, the method includes computing a joint probability density function that is descriptive of a probability that the target device is within any specified region. The method then involves applying the joint probability density function to a particular specified region to compute the probability that the location of the target device is within the particular specified region.

Methods for improving source localization based on time-of-arrival measurements

An apparatus comprises a frequency accumulator to produce a frequency ramp, and a symbol modulator to receive symbols and to add to the frequency ramp frequency offsets representative of the symbols, to produce a modulated frequency ramp for a modulated chirp. The apparatus includes a spreading factor controller to control a roll-over rate of the modulated frequency ramp responsive to spreading factor and frequency bandwidth control signals, to control a spreading factor and a frequency bandwidth of the modulated chirp. The apparatus includes a center frequency controller to control a center frequency of the modulated frequency ramp responsive to a center frequency control signal. The apparatus includes a phase accumulator to accumulate frequency samples of the modulated frequency ramp to produce phase samples corresponding to the modulated chirp, and a vector rotator to rotate the phase samples based on an input vector to produce a modulated chirp.

Efficient methods for generating chirp spread spectrum signals

In embodiments of the presently described subject matter, two efficient PAPR reduction methods for OFDM signals based upon the principle of tone reservation and building upon the clipping noise analysis presented in 'Analysis of clipping noise and tone reservation algorithms for peak reduction in OFDM systems,' L. Wang and C. Tellambura,., vol. 57, pp. 1675-1694, May 2008 are provided, each comprising two stages. The first stage is performed offline to prepare a set of cancellation signals based on the settings of the OFDM system. In particular, these cancellation signals are constructed to cancel signals at different levels of maximum instantaneous power that are above a predefined threshold. The second stage is performed online and in an iterative manner to reduce the peaks of OFDM symbols by using the cancellation signals constructed in the first stage.

Papr reduction for OFDM signals

A transmitter stores mappings of distinct values of an information signal to corresponding ones of distinct combinations of K chirps taken from M chirps that are different from each other, such that each of the distinct values is mapped to a corresponding one of the distinct combinations of K chirps. The transmitter receives a distinct value among the distinct values of the information signal. The transmitter selects, based on the mappings, a distinct combination of K chirps among the distinct combinations of K chirps that is mapped to the distinct value. The transmitter sums the K chirps of the distinct combination of K chirps to produce a symbol that represents the distinct value. The transmitter modulates the symbol to produce a modulated symbol, and transmits the modulated symbol. A receiver receives a modulated symbol that conveys a distinct value, and recovers the distinct value using stored mappings.

Methods for improving flexibility and data rate of chirp spread spectrum systems in LoRaWAN

In a digital communication system there is provided a method for OFDM channel estimation that jointly considers the effects of coarse timing error and multipath propagation. The method uses an iterative channel estimation technique, which considers the practical scenario of fractional timing error and non-sample space echo delays. The method does not require channel state information such as second-order statistic of the channel impulse responses or the noise power. Moreover, timing error can be conveniently obtained with the proposed technique. Simulation shows that, when comparing OFDM channel estimation techniques under DOCSIS 3.1 realistic channel conditions, the proposed algorithm significantly outperforms conventional methods.

Estimating the frequency response of multipath channels

Method of estimating the frequency response of multipath channels

In a DOCSIS transmission network, it is necessary for an upstream receiver to estimate and correct for errors in the carrier frequency of the transmission based upon observations of a preamble sequence. This task is complicated by the fact that microreflections in the upstream channels cause intersymbol interference, which tends to bias the frequency estimation circuit. An economical, ISI-immune algorithm is provided for estimating the carrier frequency of upstream transmissions. The arrangement improves the reliability of the frequency estimates in the presence of ISI, thereby reducing the overhead and increasing the throughput of the upstream channels.

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Saskatoon, Canada

Ha Hoang Nguyen