摘要:
Transmission parameters for a multicarrier communication channel are selected by setting a power level for each subcarrier of an active set of subcarriers, and calculating the channel capacity based on the power levels and effective noise powers. The number of active subcarriers of the set is decreased, the power levels are reset and the channel capacity is recalculated until a final set of active subcarriers result that provide the highest channel capacity.
摘要:
A transmitter may include a set of stream groups, each including two or more streams producing a set of orthogonal frequency division multiplexed (OFDM) stream-symbols and a coding unit interleaving the stream-symbols into an interleaved signal. An input bit multiplexer may route an input data signal to be divided among each of the streams. An inverse fast Fourier transform unit may operate on a combined signal formed from interleaving the interleaved signals from each stream group. Each stream may include for example a baseband signal processor producing the OFDM stream-symbols.
摘要:
A transmitter may include a set of stream groups, each including two or more streams producing a set of orthogonal frequency division multiplexed (OFDM) stream-symbols and a coding unit interleaving the stream-symbols into an interleaved signal. An input bit multiplexer may route an input data signal to be divided among each of the streams. An inverse fast Fourier transform unit may operate on a combined signal formed from interleaving the interleaved signals from each stream group. Each stream may include for example a baseband signal processor producing the OFDM stream-symbols.
摘要:
A data rate is selected for subcarriers of each frequency and spatial channel of a slowly varying frequency selective multicarrier channel to provide uniform bit loading (UBL) for faster link adaptation. Signal to noise ratios (SNRs) for subcarriers of the multicarrier communication channel may be calculated from channel state information and a transmit power level. A throughput may be estimated for the data rates from the SNRs and one of the data rates may be selected based on the estimated throughputs.
摘要:
Briefly, an adaptive transmitted power control scheme, which may be used in stations of a communication system, for example, a wireless communication system. The scheme may allocate transmission power to a communication station based on multiplying each of at least one transmitted subcarrier complex number by a corresponding subcarrier weight. Additionally, a detection scheme may detect whether a transmitted power control scheme according to an embodiment of the invention is used by stations of the communication system. The allocation of transmission power may be also used to transmit additional service information through channels.
摘要:
An adaptive multicarrier wireless communication system, apparatus and associated methods are generally disclosed herein. In at least one embodiment, channel state information is used to perform bit loading and power allocation within a multicarrier system. In an example technique, after active subcarriers have been identified for a multicarrier channel and an initial power distribution has been made, a subset of active subcarriers may be found that exceed a channel quality performance threshold. Excess power may then be identified by determining how much power could be reduced in the identified subcarriers so that they still meet, but do not exceed the channel quality performance threshold. In one possible approach, the excess power may be re-allocated to other subcarrier subsets.
摘要:
An OFDM receiver applies phase compensation to subcarriers of data symbols of an OFDM packet. A phase compensation estimate is generated from pilot subcarriers within the data symbol and applied to the subcarriers of the data symbol prior to demapping. The pilot subcarriers of the data symbol are combined and weighted to generate an observation vector. Recursive filtering is performed on the observation vector to generate the phase compensation estimate. The recursive filtering may include performing an extended Kalman-type filtering (EKF) operation on the observation vector using a channel estimate, an additive noise power estimate, a signal to noise ratio (SNR) estimate and a priori information about a dynamic model of the phase noise spectrum of transceiver oscillators. The channel estimate may be generated from a long training symbol of the OFDM packet, and the additive noise power estimate and the SNR estimate may be generated from short training symbols of the OFDM packet.