Abstract: An apparatus and method are provided for feeding back channel quality information and performing scheduling using the fed-back channel quality information in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). In the OFDMA wireless communication system, forward performance degradation due to a decrease in an amount of reverse channel quality information is reduced, and also an increase in the reverse load due to channel quality information feedback is suppressed. A base station controls power of a physical channel using information fed back from a mobile station. In a method for feeding back channel quality information from the mobile station, sub-band-by-sub-band channel quality information is measured and channel-by-channel quality information of a number of channels is transmitted in order of sub-bands of better channel quality information. Average channel quality information for a total band is measured and transmitted.

Abstract: On the transmitting side, a decision is made as to whether to add pilot symbols which are separate from basic pilot symbols, to frames, based on the propagation path state, and when symbols are added, control symbols comprising information relating to the additional pilot symbols are generated, and frames comprising basic pilot symbols, control symbols, additional pilot symbols, and data symbols are assembled and transmitted. On the receiving side, control symbols included in the received frames are demodulated, and a judgment is made as to whether additional pilot symbols are included in the received frames based on the control symbol information, and if additional pilot symbols are included, the additional pilot symbols are used to estimate the propagation path, and the propagation path estimation value is used to demodulate data symbols.

Abstract: An Ultra-Wideband (UWB) wireless communication system in a multi-user environment determines a threshold value to eliminate a signal pulse affected by a near-interference from among a plurality of signal pulses transmitted a number of times. A method for controlling an interference includes receiving the signal pulses, calculating a correlation value by applying a predetermined correlation mask to the signal pulses, determining a threshold value by referring to the number of times that the signal pulses are transmitted, a signal-to-interference-and-noise ratio, and information about a ratio of a near-interference to a far-interference, and eliminating signal pulses having a correlation value greater than the threshold value. The correlation values that are not greater than the threshold value are summed to detect a bit corresponding to each pulse signal.

Abstract: A method and terminal for feeding back channel status information, include: when the channel status information is fed back on the physical uplink control channel, code words contained in the used codebook CPUCCH(r) with a layer number or rank being r is a subset of the code words contained in the codebook CPUSCH(r) with a layer number or rank being r in the overall codebook defined in the LTE-A; wherein, the CPUCCH(r) is a single codebook or a single codebook equivalent to dual codebooks; and the CPUSCH(r) is a single codebook or a single codebook equivalent to the dual codebooks; and the single codebook equivalent to the dual codebooks refers to an actually defined single codebook in which 2 pre-coding matrix identifiers are required to determine the codebook of the code words therein for an established r.

Abstract: In various embodiments, an integrated circuit may include a number of elements configured to operate at the rate of a supplied clock signal (Single Data Rate, or SDR), and further include other elements configured to operate at twice the rate of the clock signal (Double Data Rate, or DDR). In some embodiments, the circuit may further include elements configured to transform signals between SDR and DDR. In various embodiments, the elements may select a first input during a first phase of a clock signal and select a second input during a second phase of a clock signal to provide a double data rate output. In some embodiments, the elements may form a double data rate portion of the integrated circuit that receives two bits per clock cycle and provides two output bits per clock cycle.

Abstract: A method and apparatus are described for regenerating a local clock within a wireless module and synchronizing the local clock with a wireless host clock. For one embodiment, the wireless module generates a local clock, counts the cycles of the clock during a common timing reference period maintained wirelessly between the wireless module and the host, receives a count of the host clock during the same common timing reference period, and adjusts the local clock signal based upon a comparison of the two counts. For one embodiment, the wireless module further receives timing references from the host and, in addition, receives packets of audio samples from the host accompanied by a timestamp, the timestamp based upon the host timing reference, and outputs the audio sample at the time designated by the timestamp.

Abstract: A modulation mapper selects respective data blocks (DBs) hierarchically and sequentially in a descending order of a transmission power ratio control by a gain multiplexer; decides, from a resource element group, unused REs to which modulation symbols can be allocated; and decides the allocation of modulation symbols in the REs. A channel resource element mapper performs the mapping of modulation symbols of the respective DBs to the REs on the basis for the decided allocation. A complex-value transmission signal is generated from the group of REs.

Abstract: Methods for channel estimation for OFDM schemes are provided to combat multipath fading. Scattered pilot symbols are adaptively tracked by applying a weighted summation function over the received symbols to get a “snapshot” of the pilot symbols. Channel impulse response and frequency response can then be applied to the snapshot for channel estimation. The channel estimation is then used for interpolating one or more data symbols. Furthermore, the path information of the channel impulse response can help to optimize the OFDM window position.

Abstract: The present invention relates to a method and apparatus for transmitting/receiving multimedia broadcast/multicast data. The method includes the steps of: receiving a check report returned from a receiver, determining whether the check report indicates there are both basic layer and enhanced layer data errors and if yes, exchanging the last two bits of the enhanced layer and the first two bits of the basic layer and modulating the data with a second constellation map and then transmitting the data; otherwise determining whether the check report indicates there is only the basic layer error, and modulating and transmitting the data according to the result of determination. The beneficial effects of the present invention are that the retransmission efficiency can be improved and the ratio of receiving the data correctly by the users at the cell center and at the cell border during the first retransmission is improved.

Abstract: The frequency of a digital data signal, such as a digital video signal, is intentionally varied or hopped before being sent over a network. This frequency hopping may be performed in accordance with a frequency hopping pattern shared with only intended receivers. The digital data signal may be further intentionally pre-distorted in accordance with a pre-distortion pattern which is also shared with only intended receivers. The frequency hopping and/or the pre-distortion patterns may be used to vary the frequency and modulation, respectively, on a periodic basis, such as a symbol-by-symbol or packet-by-packet basis.

Abstract: To detect the number of transmit antennas, a fast Fourier transform operation is performed on the received samples of the transmitted long training symbols of a preamble. Next, each of the Fourier transformed results is multiplied with the reference frequency-domain representation of the long training symbol so as to remove the effect of the symbols and to maintain the channel information. Next, inverse Fourier transform or least squares operations is performed on the multiplied values to compute channel impulse response. The number of shifted impulse response in the channel impulse response represents the detected number of transmit antennas. Packets containing preambles of the present invention may be received by extended devices as well as by legacy receivers that are not configured to receive and interpret these preambles. The training symbols may be cyclically-shifted and transmitted on different transmit antennas.

Abstract: A method and system for a reconfigurable orthogonal frequency division multiplexing (OFDM) chip supporting single weight diversity are provided. The reconfigurable OFDM chip may be configured to process signals such as IEEE 802.11, 802.16, and digital video broadcasting (DVB). The OFDM chip may generate channel weights to be applied to signals received in receive antennas. The weighted signals may be combined into a single received signal and channel estimates may be generated from the single received signal. Updated channel weights may be generated from the generated channel estimates. Updates to the channel weights may be performed dynamically. The configurable OFDM chip may be utilized to provide collaborative cellular and OFDM-based communication. The reconfigurable OFDM chip and the cellular chip may communicate data and/or control information via a memory coupled to a common bus.

Abstract: An apparatus for performing channel estimation includes a time-domain estimating circuit to perform a channel estimation on a time-domain received signal to output a time-domain estimated signal, a second frequency-domain converting circuit to convert the time-domain estimated signal into a frequency-domain estimated signal, an error computing circuit to produce an error signal based on the frequency-domain estimated signal and a frequency-domain received signal, and a compensation circuit to compensate the frequency-domain estimated signal using the error signal so as to produce a final channel estimation signal. The apparatus is located in a receiving device that includes a first frequency-domain converting circuit to convert the time-domain received signal into the frequency-domain received signal, and an equalizer to generate a frequency-domain recovered signal based on the frequency-domain received signal and the final channel estimation signal.

Abstract: Apparatus and methods for clock and data recovery are disclosed. In one embodiment, a clock and data recovery system includes a sampler, a deserializer, a phase detector and a frequency detector. The sampler may be configured to sample a serial data stream to produce data samples and transition samples. The deserializer may be configured to deserialize the data samples and the transition samples to produce deserialized data samples and deserialized transition samples. The deserialized data samples and the deserialized transition samples can be aligned and provided to the phase detector and the frequency detector, thereby improving phase alignment and cycle slip detection.

Abstract: A method is provided for equalizing OFDM symbol vectors received on AM in-band on-channel radio signal including a main carrier and first and second BPSK modulated subcarriers. The method comprises the steps of: computing a BPSK magnitude signal; filtering the BPSK magnitude signal; filtering complex samples received on the main carrier; using the filtered BPSK magnitude signal and the filtered complex samples received on the main carrier to compute a plurality of flat fade equalization coefficients; and multiplying the OFDM symbol vectors by the flat fade equalization coefficients. A receiver that includes an equalizer, which operates in accordance with the method is also provided.

Abstract: At least two turbo decoding apparatuses are used in a receiver for concatenated convolutional coding transmissions imbedded in 8-VSB digital television signals. This permits turbo decoding procedures for the M/H Groups in any Parade consisting of eight or fewer M/H Groups to be interleaved so at least one M/H Slot interval after each of those M/H Groups has been received is available for decoding that M/H Group.

Abstract: Apparatus and methods for rotational frequency detection are disclosed. In one embodiment, a rotational frequency detector is configured to receive samples taken from a serial data stream and to generate a frequency up error signal or a frequency down error signal. The rotational frequency detector processes a first set of samples to generate first transition data, which may be stored in a memory. The rotational frequency detector processes a second and third set of samples to generate second and third transition data. The frequency up or frequency down error signal is generated based at least partly on the first, second or third transition data. This configuration can reduce the maximum operating frequency of the rotational frequency detector, thereby simplifying the rotational frequency detector design to a point that a conventional static digital CMOS circuit design flow can be used to design the rotational frequency detector.

Abstract: Following a transmission comprising a plurality of symbols, an error measurement is generated for each symbol, so that one may distinguish between symbols having a relatively low error and symbols having a relatively high error. A bit rate to be used for subsequent transmission is determined as a function of error measurements of those symbols that have relatively low error and as a function also of the proportion of symbols having a relatively high error, such that the bit rate reduces as the proportion increases. Measurement of the error rate and/or the durations of high and low error conditions may also be used to set other transmission parameters such as error-correcting code and interleaver settings.

Abstract: In a data processing apparatus and a data processing system including the same, the data processing apparatus includes a clock signal generation unit configured to receive a data signal comprising a preamble signal, information about DC balance codes for DC balance, an embedded clock signal between the DC balance codes, and information about serialized valid data, to generate a synchronous clock signal that is synchronized with the serialized valid data based on the data signal, and to generate at least one sample clock signal based on the synchronous clock signal; and a data processor configured to deserialize the serialized valid data based on the at least one sample clock signal, to decode deserialized data based on the DC balance codes, and to output decoded data.

Abstract: A diversity reception device includes a power combiner to combine electric powers of OFDM signals, each OFDM signal being received by a first antenna and second antenna, a switch to change connections between branched output-ports of the first and second antennas, in mid-stream of effective symbol periods, the effective symbol periods are assigned respectively in each of symbol periods of the OFDM signals, a receiver to demodulate the OFDM signals, a phase shifter to shift phases of the OFDM signals received by the second antenna, and an arithmetic and control processing circuit to calculate complex correlation coefficient between a guard interval, assigned in each of the symbol periods associated with the first antenna, and a copy-source interval, assigned in each of the symbol periods associated with the second antenna, and to determine rotation angle on the basis of the complex correlation coefficient.