摘要:
A method for characterizing a communication channel is disclosed. A detection window is moved through a channel profile to accumulate tap energies in the channel profile within the detection window into an accumulated energy curve. A peak at a maximum in the accumulated energy curve is determined. A band relative to the accumulated energy curve is defined. A first arriving path (FAP) is determined using a trailing edge found near a second end of a zone in the accumulated energy curve. A leading edge is found near a first end of the zone of the accumulated energy curve. The last arriving path (LAP) is determined using the leading edge. The band defines a zone of the accumulated energy curve at or near the maximum that is within the band.
摘要:
To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.
摘要:
A method for positioning a collection window for a Fourier transform function is disclosed. A first orthogonal frequency division multiplexing (OFDM) symbol and a second OFDM symbol are received. The first OFDM symbol comprises a plurality of frequency division multiplexed (FDM) symbols. The first OFDM symbol is characterized by at least two of the following: a delay spread, a first arriving path (FAP), or a last arriving path (LAP). A channel location is estimated from a channel impulse response. A point relative to the channel location is selected. A beginning of the collection window is positioned for the second OFDM symbol at the selected point. Alternatively, a point is selected at a first location relative to the channel location using a first algorithm if a delay spread is less than a predetermined length. The selected point is chosen at a second location relative to the channel location using a second algorithm if the delay spread is greater than the predetermined length.
摘要:
A method for characterizing a communication channel is disclosed. A detection window is moved through a channel profile to accumulate tap energies in the channel profile within the detection window into an accumulated energy curve. A peak at a maximum in the accumulated energy curve is determined. A band relative to the accumulated energy curve is defined. A first arriving path (FAP) is determined using a trailing edge found near a second end of a zone in the accumulated energy curve. A leading edge is found near a first end of the zone of the accumulated energy curve. The last arriving path (LAP) is determined using the leading edge. The band defines a zone of the accumulated energy curve at or near the maximum that is within the band.
摘要:
A method for determining a communication channel location is disclosed. A first subset of a plurality of channel impulse responses is averaged over a first time period to produce a first filtered channel impulse response, and a second subset of the plurality of channel impulse responses is averaged over a second time period to produce a second filtered channel impulse response. The second time period is different from the first time period, and the second subset is different from the first subset. The communication channel location is determined using the first filtered channel impulse response and the second filtered channel impulse response.
摘要:
A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved.
摘要:
A method for positioning a collection window for a Fourier transform function is disclosed. A first orthogonal frequency division multiplexing (OFDM) symbol and a second OFDM symbol are received. The first OFDM symbol comprises a plurality of frequency division multiplexed (FDM) symbols. The first OFDM symbol is characterized by at least two of the following: a delay spread, a first arriving path (FAP), or a last arriving path (LAP). A channel location is estimated from a channel impulse response. A point relative to the channel location is selected. A beginning of the collection window is positioned for the second OFDM symbol at the selected point. Alternatively, a point is selected at a first location relative to the channel location using a first algorithm if a delay spread is less than a predetermined length. The selected point is chosen at a second location relative to the channel location using a second algorithm if the delay spread is greater than the predetermined length.
摘要:
Methods and apparatus for position location in a wireless network. In an aspect, a method is provided that includes determining whether a symbol to be transmitted is an active symbol, wherein the symbol comprises a plurality of subcarriers, and encoding identification information on a first portion of subcarriers if it is determined that the symbol is the active symbol. The method also includes encoding idle information on a second portion of subcarriers if it is determined that the symbol in not the active symbol. In an aspect, an apparatus includes detector logic configured to decode a plurality of symbols to determine identification information that identifies a plurality of transmitters, and to determine a plurality of channel estimate associated with the plurality of transmitters. The apparatus also includes position determination logic configured to calculate a device position based on the plurality of transmitters and the plurality of channel estimates.
摘要:
Methods and apparatus for position location in a wireless network. In an aspect, a method is provided that includes determining whether a symbol to be transmitted is an active symbol, wherein the symbol comprises a plurality of subcarriers, and encoding identification information on a first portion of subcarriers if it is determined that the symbol is the active symbol. The method also includes encoding idle information on a second portion of subcarriers if it is determined that the symbol in not the active symbol. In an aspect, an apparatus includes detector logic configured to decode a plurality of symbols to determine identification information that identifies a plurality of transmitters, and to determine a plurality of channel estimate associated with the plurality of transmitters. The apparatus also includes position determination logic configured to calculate a device position based on the plurality of transmitters and the plurality of channel estimates.
摘要:
Systems and methods are provided for determining position location information in a wireless network. In one embodiment, timing offset information is communicated between multiple transmitters and one or more receivers. Such information enables accurate position or location determinations to be made that account for timing differences throughout the network. In another embodiment, transmitter phase adjustments are made that advance or delay transmissions from the transmitters to account for potential timing differences at receivers. In yet another embodiment, combinations of timing offset communications and/or transmitter phase adjustments can be employed in the wireless network to facilitate position location determinations.