A signal modulation apparatus, a memory storage apparatus, and a signal modulation method are disclosed. The signal modulation apparatus includes an observation circuit, a signal modulation circuit, and a phase control circuit. The signal modulation circuit is configured to generate a second signal according to a first signal and a reference clock signal. A frequency of the first signal is different from a frequency of the second signal. The phase control circuit is configured to obtain an observation information via the observation circuit. The observation information reflects a process variation of at least one electronic component in the signal modulation apparatus. The phase control circuit is further configured to control an offset between the first signal and the reference clock signal according to the observation information.

According to various embodiments, a receiving station (STA) may receive a physical protocol data unit (PPDU). The PPDU may include a legacy signal field, a repeated legacy signal field, a first signal field, and a second signal field. The receiving STA may determine a type of the PPDU and a format of the PPDU, based on the legacy signal field, the repeated legacy signal field, the first signal field, and the second signal field.

According to various embodiments, a receiving station (STA) may receive a physical protocol data unit (PPDU). The PPDU may include a legacy signal field, a repeated legacy signal field, a first signal field, and a second signal field. The receiving STA may determine a type of the PPDU and a format of the PPDU, based on the legacy signal field, the repeated legacy signal field, the first signal field, and the second signal field.

A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder configured to encode input bits to generate an LDPC codeword including the input bits and parity bits to be transmitted in a current frame; a parity permutator configured to perform by group-wise interleaving a plurality of bit groups configuring the parity bits based on a group-wise interleaving pattern comprising a first pattern and a second pattern; a puncturer configured to puncture some of the parity-permutated parity bits; and an additional parity generator configured to select at least some of the punctured parity bits to generate additional parity bits to be transmitted in a previous frame of the current frame, based on the first pattern and the second pattern.

A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder configured to encode input bits to generate an LDPC codeword including the input bits and parity bits to be transmitted in a current frame; a parity permutator configured to perform by group-wise interleaving a plurality of bit groups configuring the parity bits based on a group-wise interleaving pattern comprising a first pattern and a second pattern; a puncturer configured to puncture some of the parity-permutated parity bits; and an additional parity generator configured to select at least some of the punctured parity bits to generate additional parity bits to be transmitted in a previous frame of the current frame, based on the first pattern and the second pattern.

A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.

A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.

Provided is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals to be transmitted over the same frequency bandwidth at the same time, including the steps of selecting a matrix F[i] from among N matrices, which define precoding performed on the plurality of baseband signals, while switching between the N matrices, i being an integer from 0 to N−1, and N being an integer at least two, generating a first precoded signal z1 and a second precoded signal z2, generating a first encoded block and a second encoded block using a predetermined error correction block encoding method, generating a baseband signal with M symbols from the first encoded block and a baseband signal with M symbols the second encoded block, and precoding a combination of the generated baseband signals to generate a precoded signal having M slots.

A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.

A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.