Cambridge Silicon Radio Limited

Samsung Electronics Co., Ltd.

Qualcomm Technologies International, Ltd.

Andrei Popescu

Chunyang Yu

Fei Tong

James Digby Yarlet Collier

Peter William Stephenson

Timothy Condren Smith

David Chappaz

Jacob Christopher Sharpe

Paul J Wright

Wei Shi

A unified device for adjacent and non-adjacent channels/carriers for processing Physical layer Protocol Data Units (PPDUs) includes a dual-use configuration capable of processing either 80+80 Megahertz (MHz) PPDUs with a single spatial stream (160/80+80 MHz 1&#xd7;1) or 80 MHz PPDUs with two spatial streams (80 MHz 2&#xd7;2).

Unified device for adjacent and non-adjacent channels for processing physical layer protocol data units

Apparatus to reduce noise in a stereo FM broadcast received via an antenna, the apparatus comprising: a frequency translator configured to translate the received stereo FM broadcast to an intermediate carrier frequency, a demodulation unit configured to demodulate the translated FM signal so as to form left-plus-right and left-minus-right AM signals, a filter configured to form a filtered signal by filtering one of the AM signals, so as to suppress a sub-band of that signal containing unwanted tones, a summing unit for summing the filtered signal and the other of the left-plus-right and left-minus-right signals to produce a stereo audio signal.

FM receiver noise reduction

A communication device capable of receiving data from a transmitting device via a communications link, the communication device comprising a buffer and being capable of generating, in dependence on the capacity of the buffer to accommodate data received over the communications link, information for inducing the transmitting device to change its data transmission rate, wherein the information imitates a change in a capability of the communication device to receive data via the communications link.

Data flow control

The present application relates to a method for reducing the peak-to-mean amplitude ratio of a transmission signal comprising a plurality of coherent replicated signals, and to a transmitted for transmitting such a signal. The transmission signal is separated into the plurality of coherent replicated signals and one of the plurality of replicated signals is delayed with respect to another of the plurality of replicated signals, either in the time domain by introducing a time delay or in the frequency domain by introducing a phase shift. This has the effect of reducing the coherence of the delayed replicated signal with respect to the other replicated signal, reducing the peak power of the signal and therefore reducing the peak-to-mean amplitude ratio of the transmission signal.

Transmitter with reduced peak-to-mean amplitude ratio

Schemes for combining channel-estimates from different OFDM frames after compensating for changes in receiver-transmitter characteristics.

Enhancing channel estimates made in digital communications receivers

A quantization method for OFDM is described. In an embodiment, the method uses an objective function which is defined as a function of the quantization error of the OFDM signal in frequency summed over data subcarriers. A search algorithm is used to optimize the objective function and the solution found is quantized by rounding. The quantized value of the solution may then be fed back into the objective function to compute a value of that function and if the value is less than the value computed in a previous iteration of the method, the method is repeated using the quantized value of the solution as the new starting point for the search algorithm. If the value of the function is, however, not less than the value computed in a previous iteration, the new solution is discarded and the quantized value of the solution from the previous iteration is output.

Quantization method for OFDM

Receiving a Wi-Fi radio signal using a Bluetooth receiver architecture. Also, adapting a Wi-Fi receiver architecture to constrain a received radio signal to less than the bandwidth of a conveyed Wi-Fi signal for subsequent processing purposes.

Schemes for the efficient reception of radio communications signals

Apparatus for reducing FM click noise on a demodulated FM signal, the apparatus comprising, filter means configured to produce a click detection signal according to the demodulated FM signal, click detection means configured to receive the click detection signal and produce a click occurrence signal, and click correction means configured to correct FM clicks on the demodulated FM signal according to the click occurrence signal.

Apparatus and method of reducing noise for frequency modulated signals

An efficient method of OFDM peak reduction is described. In an embodiment, a set of the most significant peaks in a symbol of an OFDM signal are identified and then, for each identified peak, a shifted and scaled version of a template cancellation signal is subtracted from the OFDM signal. The template cancellation signal is shifted such that its peak aligns with the identified peak and it is scaled such that it has the opposite phase to the identified peak. No iterative peak search and cancellation is involved in peak reduction, i.e. a cancellation step is not followed by another peak search for the same OFDM symbol. The process is repeated for each symbol in turn and in some embodiments the OFDM signal is up-sampled before it is analyzed to identify the most significant peaks.

Efficient OFDM peak reduction algorithm

A method of WLAN frame detection in a received signal, wherein the frame comprises first and second training sequences and the method comprises auto-correlating the signal with a delayed version of itself to establish a first frame boundary estimate based on behavior of the autocorrelation result due to the inclusion of the first training sequence in the frame, cross-correlating the signal with a copy of the second training sequence at a range of time offsets in order to generate a first cross-correlation profile, classifying the first cross-correlation profile into one of a number of categories, establishing a second frame boundary estimate from the first cross-correlation profile in a manner dependent upon the category assigned to the first cross-correlation profile and determining a refined frame boundary estimate on the basis of a consideration of the first and second frame boundary estimates. Apparatus for performing the method is also described.

Frame boundary detection

This disclosure concerns beam-forming vectors and beam-forming matrices for multiple-input, multiple-output (MIMO) communications systems. These systems, from the method perspective, provide, according to one embodiment, a method of feeding back, to a transmitter from a receiver in a MIMO communications system, at least part of a beam-forming vector of a beam-forming matrix, wherein: the vector relates to a spatial stream of the MIMO system; the vector comprises a series of elements; each element specifies a beam-forming weight for a respective transmit antenna of the transmitter; and the method comprises: calculating a scaling factor that would scale a first element of the vector to a value of one; scaling the other element or elements of the vector with the scaling factor; and feeding back the scaled other element or elements to the transmitter to inform a beam-forming process. These systems, from the method perspective, provide, according to another embodiment, a method of processing a beam-forming matrix, wherein: the beam-forming matrix is for adjusting signals that are to issue from the transmit antennae of a MIMO communications system; the MIMO communications system comprises a transmitter and a receiver; the beam-forming matrix is capable of being decomposed into a series of beam-forming vectors; each beam-forming vector relates to a spatial stream of the MIMO system; each beam-forming vector comprises a series of elements; each element specifies a beam-forming weight for a transmit antenna of the transmitter; and the method comprises: obtaining a beam-forming matrix in which the elements are quantized; and orthogonalizing the beam-forming vectors with respect to one another.

Multiple-input, multiple-output telecommunications schemes

A method of receiving a demodulated waveform according to a protocol in which the waveform represents a block of transmitted bits comprising a first group of bits and a second group of bits, the second group of bits being a function of the first group of bits, the method comprising: sampling the demodulated waveform to recover a first group of sample values corresponding to the first group of transmitted bits and a second group of sample values corresponding to the second group of transmitted bits; assigning bit values to reliable sample values of the first group of sample values; generating a set of candidates for a block of bits corresponding to the demodulated waveform, each candidate comprising a first group of candidate bits and a second group of candidate bits, the first group of candidate bits being generated using the assigned bit values and a combination of bit values unique to that candidate in the set of candidates, and the second group of candidate bits being generated by applying the said function to the first group of candidate bits; performing a correlation operation by determining a correlation between each candidate and the recovered first and second groups of sample values to form a correlation value associated with each candidate; and selecting the candidate associated with the correlation value that is indicative of the strongest degree of correlation between a candidate and the first and second groups of sample values to be the block of bits corresponding to the demodulated waveform.

Signal reception

A signal quality estimator for estimating the quality of signal reception in a signal receiver, the signal quality estimator comprising: a first filter for filtering a signal received by the receiver to isolate a frequency band therein; and a signal analyzer for forming an indication of the degree to which the amplitude of the signal in that frequency band varies over time, to serve as an estimate of the quality of signal reception in the receiver.

FM signal quality measurement

Improved power control methods and power control systems are described wherein received RSSI values are processed to generate a power control signal which may be used by a link manager, or other element in a receiving station, to determine whether to send a power control message to the transmitting station. The method used to process the received RSSI values is dependent upon a value of the power measurement, for example, the method may involve a comparison between the value of the power measurement and a value of the power control signal. In another embodiment, the received RSSI values may be converted to power values and then smoothed using a filter.

Power control method

A method for transmitting data over a network in which multiple transmission conditions can be used for transmitting data, the method comprising selecting a transmission condition to be used when transmitting data over the network, said selection being made in dependence on a predetermined preference distribution that for each of the multiple transmission conditions defines a probability of that transmission condition being selected, using the selected transmission condition when transmitting data over the network and determining the success of the transmission and updating the preference distribution in dependence on the success of the transmission and thereafter selecting a transmission condition for transmitting data over the network in dependence on the updated preference distribution.

Growing community of inventors

Cambridge, United Kingdom

Andrei Popescu