This application discloses image encoding and decoding methods and apparatuses. The image encoding method includes performing, by a source device, compression encoding on an image to obtain base layer information. The method further includes obtaining enhancement layer information based on the base layer information and the image. The method further includes obtaining control layer information. The method further includes performing encoding and modulation on the control layer information, the base layer information, and the enhancement layer information separately to obtain a plurality of symbol sets. The method further includes mapping the plurality of symbol sets to a resource for sending. Embodiments of this application may ensure robustness in a transmission process and improve overall compression efficiency and performance.

A network device determines radio frequency (RF) conditions at a first endpoint and a second endpoint of a call or session. The network device determines optimum first codec parameters for the determined RF conditions at the first endpoint of the call or session, and determines optimum second codec parameters for the determined RF conditions at the second endpoint of the call or session. The network device sends the first codec parameters to the first endpoint for altering operation of a first codec at a first device at the first endpoint. The network device sends the second codec parameters to the second endpoint for altering operation of a second codec at a second device at the second endpoint.

Techniques are described for wireless communication. One method includes segmenting a payload into a plurality of code blocks; generating, for each code block, a cyclic redundancy check (CRC); encoding each code block and associated CRC in one or more codewords of a plurality of codewords; and transmitting the codewords. The encoding is based at least in part on a low density parity check code (LDPCC) encoding type. Another method includes receiving a plurality of codewords associated with a payload encoded using a LDPCC encoding type; decoding a set of the codewords associated with the first payload and a CRC; and transmitting one of an acknowledgement (ACK) or a non-acknowledgement (NAK) for the set of the codewords.

Apparatuses for transmitting and receiving a signal in a communication system are provided. An apparatus of a receive device includes a receiver configured to receive, from a transmit device, a signal comprising remaining bits of parity bits after puncturing, wherein the parity bits are obtained by adding at least one shortened bit to information bits to obtain input bits for an encoding, if a number of the information bits is less than a number of the input bits for the encoding; and a hardware processor configured to determine a number of puncture bits for the parity bits, generate an output signal by adding at least one value corresponding to the number of the puncture bits to the signal, and decode the output signal.

An apparatus for transmitting broadcasting signal using transmitter identification and method using the same are disclosed. An apparatus for transmitting broadcasting signal according to an embodiment of the present invention includes a waveform generator configured to generate a host broadcasting signal; a transmitter identification signal generator configured to generate a transmitter identification signal for identifying a transmitter; and a combiner configured to inject the transmitter identification signal into the host broadcasting signal in a time domain so that the transmitter identification signal is transmitted synchronously with the host broadcasting signal.

A method for encoding may include receiving, at an encoder, a series of data bits, performing, at the encoder, first transition encoding on the data bits to generate an encoded series of data bits based on a key, performing, at the encoder, protection encoding on the key to generate key protection data, performing, at the encoder, second transition encoding on the key protection data to generate encoded key protection data, and transmitting an encoded series of transmission bits to a receiver, the encoded series of transmission bits including the encoded series of data bits and the encoded key protection data.

A first wireless device may receive, from a second wireless device, a transmission associated with an MLC scheme. The MLC scheme may include a plurality of bits with at least one first bit corresponding to a first level of the plurality of bits and at least one second bit corresponding to a second level of the plurality of bits. The at least one first bit may be coded with a first level of complexity, but the at least one second bit may be coded with either the first level of complexity or a second level of complexity, where the first level of complexity may be a higher level of complexity than the second level of complexity. The first wireless device may decode the at least one first bit and the at least one second bit using a decoder having a corresponding level of complexity.

Methods and apparatuses are related to multi-user parallel channel access (MU-PCA). For example, a wireless transmit/receive unit (WTRU) is provided that is one of the plurality of WTRUs operable to simultaneously communicate via a plurality of channels managed by an access point (AP). The WTRU includes a receiver configured to receive, from the AP, over at least one channel of the plurality of channels, a group poll (G-Poll) message that includes a resource allocation that indicates at least one allocated channel of the plurality of channels for the WTRU; and a transmitter configured to transmit an uplink request message, to the AP in response to the G-Poll message, over the at least one allocated channel of the plurality of channels, the uplink request message corresponding to uplink data the WTRU has for transmission to the AP.

An apparatus and method for broadcast signal frame using layered division multiplexing are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling time interleaver information shared by the core layer signal and the enhanced layer signal, using the time-interleaved signal.

An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal; a power normalizer configured to reduce power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing time-interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling start position information and size information for each of Physical Layer Pipes (PLPs). In this case, the Physical Layer Pipes include a core layer physical layer pipe corresponding to the core layer signal and an enhanced layer physical layer pipe corresponding to the enhanced layer signal.