Abstract: An apparatus, computer program and method is described including receiving data at a receiver of a communication system, generating an estimate of the data as transmitted by a transmitter of the transmission system (wherein generating the estimate includes a receiver algorithm having at least some trainable weights), generating a refined estimate of the transmitted data, based on said estimate and an error correction algorithm (wherein, in an operational mode, said estimate of the data as transmitted is generated based on the received data and said refined estimate); and generating, in the operational mode, a revised estimate of the transmitted data on each of a plurality of iterations of said generating an estimate of the transmitted data until a first condition is reached.

Abstract: A receiver, a system and a method is described comprising: receiving radio frequency signals at a plurality of receiver modules, wherein each receiver module comprises a plurality of channels, each channel comprising a receiver antenna and a mixer for converting an output of the respective antenna to an analog intermediate frequency signal having a frequency; for each of the plurality of receiver modules, combining the analog intermediate frequency signals of the respective channels into a receiver module analog intermediate frequency signal; and combining the receiver module analog intermediate frequency signals for each of the plurality of receiver modules into a composite output signal, wherein the frequency of the intermediate frequency signal of each channel of each receiver module is different. A similar transmitter, method and transmission system is also described.

Abstract: A receiver, a system and a method is described comprising: receiving radio frequency signals at a plurality of receiver modules, wherein each receiver module comprises a plurality of channels, each channel comprising a receiver antenna and a mixer for converting an output of the respective antenna to an analog intermediate frequency signal having a frequency; for each of the plurality of receiver modules, combining the analog intermediate frequency signals of the respective channels into a receiver module analog intermediate frequency signal; and combining the receiver module analog intermediate frequency signals for each of the plurality of receiver modules into a composite output signal, wherein the frequency of the intermediate frequency signal of each channel of each receiver module is different. A similar transmitter, method and transmission system is also described.

Abstract: The embodiments of the invention relate to a transmitter apparatus (TA1) for conditioning a multicarrier signal (RFS). The transmitter apparatus (TA1) contains means (FE-PU) for grouping subcarriers of the multicarrier signal (RFS) into a first frequency block, which contains a first group of the subcarriers and into at least a second frequency block, which contains at least a second group of said subcarriers. The transmitter apparatus (TA1) further contains first filtering means (LPF-1) for sideband suppression outside of the first frequency block and at least second filtering means (LPF-2, LPF-M) for simultaneous and separate sideband suppression outside of the at least second frequency block. The embodiments of the invention further relate to a method for conditioning a multicarrier signal (RFS).

Abstract: The embodiments of the invention relate to a transmitter apparatus (TA1) for conditioning a multicarrier signal (RFS). The transmitter apparatus (TA1) contains means (FE-PU) for grouping subcarriers of the multicarrier signal (RFS) into a first frequency block, which contains a first group of the subcarriers and into at least a second frequency block, which contains at least a second group of said subcarriers. The transmitter apparatus (TA1) further contains first filtering means (LPF-1) for sideband suppression outside of the first frequency block and at least second filtering means (LPF-2, LPF-M) for simultaneous and separate sideband suppression outside of the at least second frequency block. The embodiments of the invention further relate to a method for conditioning a multicarrier signal (RFS).

Abstract: Proposed is a method of decoding a differentially encoded PSK modulated optical data signal carrying FEC encoded data values. The optical signal is corrected by an estimated phase offset. From the corrected signal, respective likelihood values for the FEC encoded data values are derived, using an estimation algorithm which accounts for a differential encoding rule used for differentially encoding the optical signal. The derived likelihood values are limited to a predetermined range of values. From the limited likelihood values, FEC decoded data values are derived, using an algorithm which accounts for a FEC encoding rule used for FEC encoding the FEC encoded data values.

Abstract: Proposed is a method of deriving differentially decoded data values from a received differentially encoded phase modulated optical signal. The method uses an estimation algorithm in order to find derive a sequence of differentially decoded data values. The algorithm stipulates transition probabilities between hypothetical first states, representing differentially encoded data symbols assuming that no phase slip has occurred, and transition probabilities towards hypothetical second states, which represent differentially encoded data symbols assuming that a phase slip has occurred. The transition probabilities between the first and second states are weighted on the basis of a predetermined phase slip probability value.

Abstract: Proposed is a method of decoding a differentially encoded PSK modulated optical data signal carrying FEC encoded data values. The optical signal is corrected by an estimated phase offset. From the corrected signal, respective likelihood values for the FEC encoded data values are derived, using an estimation algorithm which accounts for a differential encoding rule used for differentially encoding the optical signal. The derived likelihood values are limited to a predetermined range of values. From the limited likelihood values, FEC decoded data values are derived, using an algorithm which accounts for a FEC encoding rule used for FEC encoding the FEC encoded data values.

Abstract: Proposed is a method of deriving differentially decoded data values from a received differentially encoded phase modulated optical signal. The method uses an estimation algorithm in order to find derive a sequence of differentially decoded data values. The algorithm stipulates transition probabilities between hypothetical first states, representing differentially encoded data symbols assuming that no phase slip has occurred, and transition probabilities towards hypothetical second states, which represent differentially encoded data symbols assuming that a phase slip has occurred. The transition probabilities between the first and second states are weighted on the basis of a predetermined phase slip probability value.

Abstract: An concept for providing first data detection information on a first data signal of a first mobile transceiver and second data detection information on a second data signal of a second mobile transceiver, comprising means (110) for communicating with the first mobile transceiver for receiving a first receive signal vector from the first mobile transceiver, the first receive signal having been received from a base station transceiver by the first mobile transceiver, and means (120) for communicating with the second mobile transceiver for receiving a second receive signal vector from the second transceiver, the second receive signal having been received from the base station transceiver by the second mobile transceiver.

Abstract: An apparatus for and a method of performing packet detection in a receiver is provided. The apparatus is configured to determine a measure of a correlation between information of one or more received symbols and synchronization information. The apparatus is also configured to determine a measure of an energy value of one or more of the received symbols. The apparatus is also configured to determine if a packet has been detected based on the measure of the correlation and the measure of the energy value of the one or more received symbols.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: Methods and systems for packet preamble sequences are provided. The preamble sequences are produce by multiplying preestablished base sequences by cover sequences. The cover sequences are chosen for high-performance in multi-band OFDM systems with modes that include two-band hopping.

Abstract: A method and system for detecting the presence of narrowband transmitters utilizing frequencies also utilized by wider band communication systems. In some embodiments an ultrawideband transceiver detects signals at specific frequencies within a spectrum of frequencies, and analyzes the signals to determine if the signals indicate transmissions by a narrowband transmitter in a narrowband communication system. In further embodiments transmission circuitry reduces signal components at frequencies occupied by the narrowband transmitters.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a mixer are adjusted during a first and coarse automatic gain control stage based on feedback from a digital baseband stage. During a subsequent fine gain control period, the gain of a programmable gain amplifier is adjusted separately for each frequency band used by the OFDM symbols based on a histogram bin that counts the number of output samples of an analog to digital converter whose magnitude falls within certain ranges. Coarse and fine gains are updated after each OFDM symbol.

Abstract: A method and a receiver system for subcarrier-specific frequency offset correction including frequency offset estimation, updating and compensation. The method includes initial frequency offset estimation in time domain using packet preamble, frequency offset compensation during channel estimation symbols using the initial frequency offset estimate, and frequency offset update tracking during header and data part both being performed in the frequency domain. The initial frequency offset estimation includes using a sum over a number of time lagged autocorrelation results, corresponding to a number of the last consecutive symbols of the preamble part of the packet with the autocorrelations being the result of a sum over a window of cross-correlations between the incoming signal and the respective packet synchronization sequence.

Abstract: A receiver including a channel estimation function in which an initial channel estimate is filtered to increase receiver operation, particularly when the receiver may only have a limited number of channel estimation symbols with which to form the channel estimate. In some embodiments the filtering is performed by transforming the initial channel estimate to the time domain, zeroing some of the samples to filter the time domain channel estimate, and transforming the filtered time domain channel estimate to the frequency domain for use in channel compensation.