Nortel Networks Corporation

Huawei Technologies Co., Limited

Northern Telecom Limited

Wolfgang W Oberhammer

Kim Bryon Roberts

Bixia Li

Peiying Zhu

Osama S Aboul-Magd

Jung Hoon Suh

Kwok Shum Au

Sheng Sun

Maurice M O'Sullivan

Roland A Smith

Song Zhang

Michael Moher

Eddy Shi-Ning Hum

Andy Rowland

James Gary Griffiths

Mark Elwood Driedger

System and method embodiments are provided for analog cancellation for division free duplexing for radios using MIMO. In an embodiment, a system for minimizing transmitted signals from a transmitter appearing at a co-located receiver in a division free duplexing radio includes a transmitter to transmit an analog transmitted signal; an antenna; a circulator coupled to the transmitter and the antenna; a tuning algorithm component configured to receive a copy of the analog transmitted signal from the transmitter and a sampled analog received signal from a received signal path from the circulator, wherein the sampled analog received signal is sampled at a point in the received signal path before the analog received signal is provided to a receiver; and a multitap cancellation component configured to provide a cancellation signal to couple to the analog received signal such that an amount of the analog transmitted signal appearing at the receiver is reduced.

Systems and methods for analog cancellation for division free duplexing for radios using MIMO

In one embodiment, a collaborative service set (CSS) includes a controller access point (AP) configured to be associated with a first plurality of stations and a first member AP, where the first member AP is associated with a second plurality of stations, where the controller AP is configured to coordinate transmissions between the first member AP and the second plurality of stations with transmissions between the controller AP and the first plurality of stations, where the controller AP and the first member AP are configured to transmit messages simultaneously.

System and method for a collaborative service set

A method and system for reducing non-linear signal degradation effects of WDM optical signals exacerbated by highly correlated bit patterns of optical waveforms in neighboring optical channels. Embodiments include offsetting the transmission times of signals in neighboring channels, and applying different scrambling patterns to the respective data streams prior to transmission on neighboring optical channels.

Decorrelation of WDM signals

A framer is adapted for framing a high error rate data signal received through a link of a communications network, the data signal comprising M (an integer, M&#x3e;1) interleaved sub-streams. The framer includes means for detecting a respective unique synchronizing word within each sub-stream. Each respective unique synchronizing word comprises: a non-unique position word having a first predetermined hamming distance; and a non-unique identifier word having a second predetermined hamming distance. The framer preferably includes M individual framers, and a master framer. Each individual framer operates to search the data signal to detect a respective one of the respective unique synchronizing words; and assert a respective individual frame found state for a first predetermined period of time when a respective one of the unique synchronizing words is found. The master framer controls operations of each individual framer, and declares a master frame lock state if the individual frame found state is asserted by all of the individual framers within a second predetermined period of time.

Spectrally invisible framing of high error rate data signals

A method and apparatus for using sacrificial bits in a data stream to adjust sampling parameters for the data stream is described. The sacrificial bits are a predetermined sequence of a predetermined length. The sampling parameters are perturbed during transmission or reception of the sacrificial bits in order to provide information useful in adjusting the sampling parameters of the apparatus. Adjustment is accomplished by computing a bit error rate during the perturbing of sampling parameters in order to probe edges of an eye closure of the detected signal. The advantage is faster homing on optimal sampling parameters with little sacrifice of transmission capacity.

Method and apparatus for optimization of a data communications system using sacrificial bits

At a transmitter, a measurement array is constructed from various combinations of frame bits, including at least one combination Which includes many frame bits and at least one combination which includes only a few frame bits. The measurement array is transmitted along with the frame bits. Upon receipt of the frame at a receiver, a parity check is performed on the received frame bits and on the measurement array, resulting in the creation of a symptomatic array. The symptomatic array can be accumulated during the course of successive frames. After a sufficiently high number of frames, it will become clear from the values of the elements in the accumulated symptomatic array which bits in the symptomatic array are saturated and which are not. The accumulated symptomatic array is then mapped to a BER estimate.

Method and system for estimating error rate of a communication channel over a wide dynamic range

An RF receiver, which is one of a network of receivers, is described which allows for a simple method of compensating for the group time delay asymmetry of an IF filter in the receiver. Compensation of the group time delay is important for time difference of arrival (TDOA) measurements for mobile location tracking applications, such as E-911 applications. The TDOA measurements are performed by the receiver network. The RF receiver includes a switch which alternately switches between two RF LO frequencies for consecutive pulse signals received from a mobile transmitter. One of the two RF LO frequencies is offset by the IF frequency on the positive side of the center frequency of the mobile transmitter signal received by the receiver. The other RF LO frequency is offset by the IF frequency on the negative side of the center frequency. The group time delay of the IF filter may be compensated for by switching between the two RF LO frequencies, performing a time of arrival (TOA) measurement for the signals corresponding to each of the RF LO frequencies, and averaging the group time delays for each TOA. A TOA estimator causes the switch to switch an RF LO oscillator between the two RF LO frequencies. A method for compensating for the group time delay asymmetry corresponding to the receiver is also described.

Method of compensating for group time delay asymmetry in a radio receiver

A digitizer with increased dynamic range is provided by applying varying gains/attenuations to an input signal and feeding the resulting scaled signals to several conventional analog-to-digital converters to be digitized. The digitized version of the largest scaled signal which does not result in its respective analog-to-digital converter from saturating is selected by a multiplexer to be fed through as the digitizer output. Each of the gains(attenuations) differ by multiples of approximately 6 dB, since one bit in an ADC represents this value. The multiplexer outputs a digital sample size which is larger than that of the analog-to-digital converters and with the selected digitized version being output as the appropriate subset of the larger sample size to account for the gain(attenuation) of the selected signal. Preferably, this is used in a wideband receiver to increase the dynamic range of the receiver.

Dynamic range extension of wideband receiver

A coupled oscillator arrangement is provided comprising first and second VCOs (voltage controlled oscillators), and a bi-directional interconnect which injection locks the first and second VCOs to each other. Advantageously, this provides a mechanism which effectively eliminates the phase jitter between the phase of first and second VCOs which makes them suitable for use in a diversity receiver, while at the same time providing a redundancy arrangement in which the failure of one of the VCOs does not effect the functionality of the other. The use of a bi-directional interconnect minimizes the complexity and cost of coupling the two VCOs. Preferably, the bi-directional interconnect injects a first signal representative of an output signal of the first VCO to the output of the second VCO and injects a second signal representative of an output signal of the second VCO to the output of the first VCO.

Method and apparatus for the injection lock of redundant oscillators

A wideband receiver capable of handling the new extended A and B cellular spectrum is provided. Portions of the band are converted using analog conversion into a frequent between Fs/4 and Fs/2 where Fs is a sampling frequency of an analog-to-digital converter. Other portions of the band are converted such that when they are sampled by the analog-to-digital converter aliasing causes them to lie in the baseband frequencies between zero and Fs/2, and more particularly in baseband frequencies which do not interfere with the other converted bands.

Wideband receiver with bandwidth extension

A radio transceiver system uses a single variable local oscillator frequency source which is used in mixing both before and after a band-pass filter. This causes a reduction in band-pass filter bandwidths. In an all-band transceiver for PCS for example the effect of this reduced bandwidth requirement is to increase the spacing between the transmit bands and the receive bands and thereby enable a reduction in transmission noise interfering with the reception bands.

Transceiver bandwidth extension using double mixing

A planar filter connector is disclosed for the transmission of signals to be passed in and out of an EMI shielded enclosure. The EMI enclosure has walls the free ends of which are provided with an electrically conductive, resilient gasket. The filter connector is located on a conductive pad on a printed circuit board and is positioned under a portion of one of the walls, the gasket being depressed to accommodate the filter connector. The connector consists of a planar conductor surrounded by high dielectric material and further surrounded by two planar metallization layers. One metallization layer is in electrical contact with the gasket and the other metallization layer is in contact with the conductive pad. Shielding through the connector is maintained by the capacitance created between the conductor and each of the metallization layers.

Surface mount EMI gasket filter

An amplifier circuit has an amplifying transistor which is switched on and off by a switching transistor under control of a control signal selectively applied to the switching transistor. In this way a selection is made whether or not to amplify an input signal on an antenna. The switching transistor forms part of the biasing circuit for the amplifying transistor such that when the switching transistor is on the amplifying transistor is biased off. A PIN diode and series resistor are together connected in shunt across the switching transistor such that the bias voltage which causes the amplifying transistor to be off causes the PIN diode to be forward biased thereby causing the antenna to be terminated with the resistor the value of which may be chosen to be 50 ohms.

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Ottawa, Canada

Wolfgang W Oberhammer