A fading assessment unit 34 assesses the degree of fading of a received radio wave. An SNR calculation unit 33 calculates an SNR value of a signal based on the radio wave. A communication mode determination unit 35 determines the communication mode of communication from a transmission side of the radio wave on the basis of the result of the assessment by the fading assessment unit 34 and the SNR value calculated by the SNR calculation unit 33.

A system for enabling signal penetration into a building includes first circuitry, located on an outside of the building, for receiving signals at a first frequency that experiences losses when penetrating into an interior of the building and converting the received signals at the first frequency into a first format that overcome the losses caused by penetrating into the interior of the building over a wireless communications link. The first circuitry further includes a first transceiver, implementing a first transmission chipset for RF transmissions in the first format that counteracts losses occurring when penetrating into the interior of the building, for receiving the signals at the first frequency and converting the received signals at the first frequency into the first format that overcomes the losses caused by penetrating into the interior of the building. Second circuitry, located on the interior of the building is communicatively linked with the first circuitry for receiving and transmitting the converted received signals in the first format. The second circuitry further includes a second transceiver, implementing the first transmission chipset, for receiving and transmitting the converted signals in the first format from/to the first transceiver on the exterior of the building.

A synchronizing radio receiver is disclosed, comprising: an analog baseband receive chain and a digital baseband receive chain. The digital baseband receive chain may comprise an analog to digital converter, a frame synchronization module, a frequency synchronization module, and an orthogonal frequency division multiplexing (OFDM) demodulator, wherein the frequency synchronization module is configured to cross-correlate a plurality of in-phase and quadrature samples to generate a synchronization signal and output the synchronization signal to a local oscillator in the analog baseband receive chain. The digital baseband receive chain may also further comprise a carrier frequency offset (CFO)/sampling frequency offset (SFO) correction module coupled to a frequency synchronization module configured to cross-correlate a plurality of in-phase and quadrature samples, with the CFO/SFO correction module configured to apply correction in a digital domain before outputting a corrected signal to the OFDM demodulator.

A system for enabling signal penetration into a building includes a first transceiver, located on an outside of the building, for transmitting and receiving signals at a first frequency outside of the building, wherein the signals at the first frequency do not easily penetrate into an interior of the building. A first up/down converter converts between a first version of the signals at the first frequency and a second version of the signals at a second frequency. The first frequency is higher than the second frequency and the signals at the second frequency better penetrate to the interior of the building and overcome losses caused by penetrating into an interior of the building. A second up/down converter converts between the second version of the signals at the second frequency that overcomes the losses caused by penetrating into the interior of the building and a third version of the signals after transmission from the building exterior to the building interior. A router transmits and receives the third version of the signals within the interior of the building.

A system for enabling signal penetration into a building includes a transceiver located on an exterior of the building for receiving signals at a first frequency transmitted from a source outside of the building. An optical bridge receives the signals at the first frequency that experiences losses when penetrating an exterior surface of the building, converts the received signals at the first frequency into a first format that overcome losses caused by penetrating an exterior surface of the building and transmits the signals through the exterior surface of the building. A WiFi transceiver located on the interior of the building and connected to the optical bridge converts between the signals in the first format and WiFi signals and for transmitting the WiFi signals to the interior of the building and receiving the WiFi signals from the interior of the building.

Receivers including estimation unit (EU) circuits and related processing techniques for wireless systems are provided. Efficient expressions for quadrature amplitude modulation (QAM) symbol mean and variance calculations are utilized with efficient expressions and implementations that are adaptive to different orders of QAM formats. An EU circuit includes a mean estimation unit (MEU) circuit and/or second moment estimation unit (SEU) circuit. Each estimation unit circuit is configured to receive a variable QAM normalization factor so that the circuit can be adapted to different QAM orders. Each MEU or SEU circuit can be configured for sequential and/or parallel processing. A pool including multiple MEU circuits and/or a pool including multiple SEU circuits is provided in one embodiment, with a control unit for configuring and reconfiguring the pools of circuits for mean and variance estimation for data streams of QAM symbols.

The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data rate beyond a 4G communication system such as LTE. According to an embodiment of the present invention, a method for transmitting a synchronization signal by a base station in a filter bank multi carrier (FBMC) system and a base station using the same may be provided, the method comprising the steps of: generating a frequency-domain quadrature amplitude modulation (QAM) symbol sequence having a length of k for a synchronization signal; mapping the QAM symbol sequence to a sub-carrier of a filter bank on the basis of the correlation characteristic of the synchronization signal; generating a quadrature amplitude modulation-filter bank multicarrier (QAM-FBMC) symbol including the synchronization signal on the basis of the mapping, and transmitting the generated QAM-FBMC symbol. In addition, a terminal communicating with the base station and an operation method for the terminal may be provided.

Message faults are expected to become a major problem for next-generation 5G/6G networks, due to signal fading, high backgrounds, and high density of users. Disclosed are methods to modulate and demodulate messages to optimize noise margins, greatly enhancing reliability at negligible cost, according to some embodiments. A transmitter can modulate a message using amplitude-phase modulation, yet a receiver can conveniently receive and process the signals according to separate in-phase (I) and quad-phase (Q) branches, that is, according to QAM. The receiver can then convert the I and Q values to the original waveform amplitude and phase mathematically, and then demodulate those values using predetermined amplitude and phase levels as provided by a proximate demodulation reference. By converting the as-received QAM values to the as-transmitted amplitude-phase values, the receiver can thereby avoid many noise vulnerabilities inherent in QAM-modulated messages, and thereby obtain the full noise margins provided by amplitude-phase modulation.

A method, system, and apparatus are provided for computing soft bits in a non-linear MIMO detector which decodes a signal received at a plurality of receive antennas using channel estimate information and a decoding tree to produce output data for a bit estimation value which includes a maximum likelihood solution along with a naturally ordered vector identifying all explored node metrics and node indices, where soft bits are computed for each bit estimation value by determining a set of bit-masks through repetition and indexing operations applied on the explored node indices, masking the naturally ordered vector with the set of bit-masks to generate masked node metrics, determining candidate soft bit values by subtracting metrics of all nodes that form the maximum likelihood solution from the masked node metrics, and determining a final soft bit value by identifying which of the candidate soft bit values has a lowest value.

A method of designing a digital filter for example for use in an FBMC/OQAM telecommunications system, with a target overlapping factor and meeting a specified signal to interference ratio is described, whereby a candidate filter design defined by an impulse response, satisfying the Nyquist criterion and having an overlapping factor higher than the target is selected, and the time and frequency coefficients of its impulse response inverted to define a new filter design; and truncating the impulse response defining said new filter design to the minimum number of coefficients achieving said specified signal to interference ratio.