Abstract:
Transmitting data in a digital video broadcasting for handheld (DVB-H) receiver comprises a transport stream (TS) demultiplexer adapted to extract internet protocol (IP) datagrams from TS data packets; a packet identifier (PID) filter adapted to extract the TS data packets based on the PIDs of the TS data packets; a Multi Protocol Encapsulation-Forward Error Correction (MPE-FEC) random access memory (RAM) unit operatively connected to the TS demultiplexer; a Reed-Solomon decoder operatively connected to the MPE-FEC RAM unit; an IP to TS encapsulator operatively connected to the MPE-FEC RAM unit; a TS multiplexer operatively connected to each of the PID filter and the IP to TS encapsulator, wherein the TS multiplexer is adapted to combine both DVB-Terrestrial (DVB-T) and DVB-H TS data packets into a single combined TS data packet; and a host interface operatively connected to the TS multiplexer.
Abstract:
A technique for decoding code packets of file delivery protocol (FDP) and file delivery control protocol (FDCP) messages, the FDP messages comprising fields having values used to generate an indices of a data packets, the FDCP messages comprising a value of a minimum number of code packets required, the code packets formed from a linear combination of the data packets of a file fragment, the method includes constructing data structures adapted to decode the code packets of the file fragment, the data structures comprising at least one of code nodes, a code graph, an inverse code graph, a data packet decode array, and a data packet decode order list, processing the FDP messages until a parameters required for decoding are extracted, and populating the inverse code graph with a reference to the code node.
Abstract:
An apparatus, system, and method of performing adaptive frequency domain equalization in an Orthogonal Frequency Domain Multiplexing (OFDM) based communication system transmitting data information, wherein the method comprises receiving OFDM symbols comprising scattered pilots; obtaining channel estimates on every third bin of the scattered pilots in a frequency domain, wherein the channel estimates are obtained by performing an interpolation in a time domain across the received OFDM symbols; estimating an original channel based on the channel estimates, wherein the original channel in the time domain is estimated by applying a finite impulse response (FIR) low-pass filter in a frequency domain, wherein the FIR low-pass filter is adaptive according to a delay span of an original channel impulse response and is sufficiently wide to cover the delay span of the original channel impulse response; and dividing the received OFDM symbols by the channel estimate to obtain transmitted data information.
Abstract:
A method for correlating scattered pilot locations in a sequence of OFDM symbols in a multi-carrier transmission system, and includes mapping pilot locations comprising pilot symbols having predetermined known values, wherein the pilot symbols are positioned among data subcarriers in time and frequency dimensions consisting of received pilot symbols and having a predetermined position pattern in the time and frequency dimensions, wherein the predetermined position pattern comprises a finite number of sub-position patterns each corresponding to positions of the pilot symbols; estimating a Doppler spread in a frequency spectrum between the transmitter and the receiver in the multi-carrier transmission system; estimating a channel length of a set of channel paths received at the receiver; and the receiver automatically selecting one of a plurality of predetermined methods of correlating the scattered pilot locations in the sequence of OFDM symbols based only on the estimating processes.
Abstract:
An apparatus, logic, and method of performing timing and frequency estimation in a MediaFLO™ mobile multimedia multicast system comprising a receiver and a transmitter, wherein the method comprises receiving a wireless data stream comprising a MediaFLO™ mobile multimedia multicast system superframe comprising Orthogonal Frequency Division Multiplexing (OFDM) symbols; estimating a Fast Fourier Transform (FFT) trigger point for each of the received OFDM symbols; estimating a fine carrier frequency offset of each OFDM symbol; determining the start of the MediaFLO™ mobile multimedia multicast system superframe by locating a Time Division Multiplexed (TDM) pilot symbol in the superframe; estimating a coarse carrier frequency offset of each of the received OFDM symbols; and synchronizing the receiver to the start of the MediaFLO™ mobile multimedia multicast system superframe and the transmitted OFDM symbols based on the fine carrier frequency offset, the TDM pilot symbol, and the coarse carrier frequency offset.
Abstract:
ICI canceling in an OFDM system includes taking a FFT of a wireless electrical signal to produce an OFDM signal; estimating a DC component of a frequency-selective channel in the OFDM system; obtaining an initial estimate of data symbols associated with data bits of the OFDM signal; correcting the data bits with a Viterbi decoder; encoding the corrected data bits to acquire corrected data symbols; re-estimating the DC component of the frequency-selective channel using the corrected data symbols; filtering the corrected data symbols and sub-carrier of the frequency-selective channel; calculating a first order differential function of the frequency-selective channel based on successive ones of the corrected data symbols; removing an ICI component from the calculated first order differential function; and re-estimating the data symbols as a function of the removed ICI component. The filtering occurs using a low pass filter comprising a bank of eight filters.
Abstract:
Digital autonomous AGC for a DVB-H receiver comprises detecting a plurality of RF signals entering a LNA in the DVB-H receiver; detecting a RF transmitter blocker signal occurring at the LNA; and differentiating between a desired RF signal and an undesired RF transmitter blocker signal by varying a differential gain of current through the LNA. A RF servo loop is used for detecting the RF transmitter blocker signal. Logic circuitry of the RF servo loop is integrated with a baseband AGC loop to step control the differential gain of current through the LNA. A RF wideband detector is used for detecting the plurality of RF signals entering the LNA; and sending a voltage output corresponding to voltage levels of the RF signals to a plurality of comparators, wherein each of the plurality of comparators are set at a different programmable voltage threshold level compared with one another.
Abstract:
An apparatus, system, and method of performing adaptive frequency domain equalization in an Orthogonal Frequency Domain Multiplexing (OFDM) based communication system transmitting data information, wherein the method comprises receiving OFDM symbols comprising scattered pilots; obtaining channel estimates on every third bin of the scattered pilots in a frequency domain, wherein the channel estimates are obtained by performing an interpolation in a time domain across the received OFDM symbols; estimating an original channel based on the channel estimates, wherein the original channel in the time domain is estimated by applying a finite impulse response (FIR) low-pass filter in a frequency domain, wherein the FIR low-pass filter is adaptive according to a delay span of an original channel impulse response and is sufficiently wide to cover the delay span of the original channel impulse response; and dividing the received OFDM symbols by the channel estimate to obtain transmitted data information.
Abstract:
Protocol stack layer processing for a MediaFLO™ mobile multimedia multicast system comprising a transmitter comprising a host processor and a host memory component. The processing includes a receiver that receives a wireless data stream comprising a MediaFLO™ mobile multimedia multicast system superframe comprising any of audio, video, and text media frames arranged in multiplexed Multicast Logical Channels (MLCs) and received from the transmitter, wherein each MLC is divided into 16 byte data packets, and wherein each MLC carries up to three logical sub-channels comprising stream 2, stream 1, and stream 0; and an Application Specific Integrated Circuit (ASIC) memory component operatively connected to the receiver, wherein the ASIC memory component performs processing of the data packets using hardware components comprising, a Medium Access Control (MAC) layer core; a stream layer core; a decryption layer core; a defragmentation layer core; and a sync layer core.
Abstract:
A method of estimating coarse frequency offset of received symbols based on a received frequency domain sample at a kth sub-carrier of a 53rd Orthogonal Frequency Division Multiplexing (OFDM) data symbol in a jth time slot (TS) of a receiver in a China Multimedia Mobile Broadcasting (CMMB) mobile television network includes dividing a received sample, Ykj, into two sets of noise only tones and data plus noise tones Dkj, obtaining a received sample only if there is a coarse frequency offset mismatch between a transmitter and the receiver, dividing a summation of a power of the data plus noise tones by a summation of a power of the noise only tones to obtain Λkj, and estimating an integer coarse frequency offset estimate, Δ{circumflex over (f)}Ij, of the received symbols when the Λkj is a maximum.