摘要:
A method of estimating frequency offset of a received signal in a terminal apparatus comprises a) determining a phase change between a first and a second reference symbol of the received signal, wherein the time distance t between the first and the second reference symbols is associated with an observation frequency f such that f=1/t. The method further comprises: b) determining a preliminary frequency offset Δf based on the determined phase change, wherein Δf forms a frequency offset hypothesis Δfh; and c) decoding at least a part of the received signal, with application of the frequency offset hypothesis Δfh, to a decoded signal. The method further comprises: d) determining whether the decoded signal is a successful decoding. If the decoded signal is a successful decoding, the frequency offset hypothesis Δfh is determined to be the estimated frequency offset, but if the decoded signal is not a successful decoding, the frequency offset hypothesis Δfh is adjusted by an integer n times the observation frequency f such that Δfh=Δf+n·f, where nε[+/−1, 2, 3, . . . ]. Steps c) and d) are then repeated.
摘要:
Methods and arrangements in a first network node, a second radio network node and a mobile terminal for enabling estimation of a position of a mobile terminal are provided. The first network node receives a request for estimating the position of the mobile terminal. The first network node determines a first set of radio network nodes including the second radio network node and two additional radio network nodes. The first network node determines positioning signals for transmission from radio network nodes of the first set to the mobile terminal. The first network node instructs each of the radio network nodes of the first set to transmit the positioning signal, associated therewith, to the mobile terminal.
摘要:
A mobile station comprises a radio communication unit (22) for communicating with a radio communication network for finding carriers on which transmissions are being made in active transmission intervals of a transmission cycle following a discontinuous transmission scheme. The radio communication unit is configured to select a carrier based on probability settings provided for each carrier of the scheme, scan the selected carrier during a time range that is a fraction of the transmission cycle, confirm the presence of the carrier if transmissions are detected and otherwise to adjust the probability settings of the carriers based on the timing of the scanning and the position of the carrier active transmission interval in the transmission sequence and repeat the selection of carrier based on probability settings and adjusting of probability settings until the presence of a carrier has been confirmed.
摘要:
Allocation of cell IDs in a cellular communication system includes determining a candidate allocation pattern of primary and secondary synchronization signal sequences for a candidate set of two or more cells. A performance metric is applied to the candidate allocation pattern to ascertain a performance indicator for the candidate allocation pattern, wherein the performance indicator indicates a quality of positioning performance for the candidate set of two or more cells. Cell-specific positioning performance for each cell in the candidate set of cells can be considered to derive the performance indicator of the candidate allocation pattern. If the performance indicator indicates acceptable positioning performance, primary and secondary synchronization signal sequences are allocated to respective ones of base stations corresponding to the two or more cells in accordance with the candidate allocation pattern. Otherwise, the process is repeated for a different candidate allocation pattern.
摘要:
Methods and apparatus are provided for detecting the radio access technology (RAT) employed in a received signal prior to performing a cell search. The RAT detection method may be used to identify the most likely RAT employed for each candidate frequency identified in an initial frequency scan. Once the most likely RAT is identified, the mobile communication device can then attempt synchronization according to the procedures for the most likely RAT. Identifying the RAT prior to the cell search reduces the number of synchronization attempts and, consequently, the time needed to perform the cell search.
摘要:
There is disclosed a method of estimating frequency offset of a received signal in a terminal apparatus operating in a wireless communication system. The method comprises a) determining a phase change between a first and a second reference symbol of the received signal, wherein the time distance t between the first and the second reference symbols is associated with an observation frequency f such that f=1/t; b) determining a preliminary frequency offset Δf based on the determined phase change, wherein the preliminary frequency offset Δf form a frequency offset hypothesis Δfh; c) decoding at least a part of the received signal, with application of the frequency offset hypothesis Δfh, to a decoded signal; d) determining whether the decoded signal is a successful decoding, wherein if the decoded signal is a successful decoding, determining the frequency offset hypothesis Δfh to be the estimated frequency offset, and if the decoded signal is not a successful decoding, adjusting the frequency offset hypothesis Δfh by an integer n times the observation frequency f such that Δfh=Δf+n·f, where nε[+/−1, 2, 3, . . . ], and repeating steps c) and d). Computer program, frequency controller, and terminal apparatus are also disclosed.
摘要:
A terminal with transmitter and receiver operates in a multi-carrier communication system and receives at least two downlink carriers. One or more timing advance commands are received, each associated with a group of one or more uplink carriers, each group being associated with one or more of the received downlink carriers. For each downlink carrier associated with one of the groups of uplink carriers, one is selected as a reference downlink carrier; the reference downlink carrier timing is ascertained; and a transmission time period is ascertained based on the timing of the downlink reference carrier and an offset specified by the timing advance command associated with the group of uplink carriers. The transmission time period comprises a start time and a stop time. Transmission is initiated at an earliest transmission start time of the ascertained transmission time periods and is ceased at a latest ascertained stop time.
摘要:
A receiver receives and front-end processes a plurality of component carrier signals, each carrier spaced apart in frequency. The digitized, baseband component carrier signals are inspected to determine estimates of timing offsets between the carriers. A control unit selects a first component carrier signal having data scheduled to the receiver. If data is scheduled to the receiver on other component carrier signals, the control unit generates timing and frequency offset adjustment control signals to time- and frequency-align each other component carrier signal having relevant data, to the first component carrier signal. All the relevant component carrier signals are then combined, and a single OFDM symbol, spanning all the relevant component carriers, is presented to an FFT for symbol detection.
摘要:
A wireless communication system receiver receives and processes a signal comprising at least two component carriers carrying data scheduled to the receiver and having center frequencies spaced apart by at least one component carrier frequency difference. Each component carrier comprises a number of subcarriers spaced apart by a system subcarrier frequency spacing. A common divisor is obtained for the at least one component carrier frequency difference and the system subcarrier frequency spacing. A symbol is received on the subcarriers of the component carriers and downconverted to baseband to produce a baseband symbol. A block of padding values is inserted in the baseband symbol to produce a padded symbol. The length of the block of padding values is such that intermediate subcarriers are inserted to yield a subcarrier frequency spacing for the padded symbol equal to the common divisor. Finally the padded symbol is Fast Fourier Transform, FFT, processed.
摘要:
Methods and apparatus in a receiver for estimating a received power of at least one signal having a pattern known to the receiver, the signal having being transmitted by at least one antenna. A method includes using a first method of measuring the received power based on the pattern, the first method generating a first sequence of first power estimates; determining whether a predetermined first event has occurred; and if the first event has occurred, changing to a second method of measuring the received power, the second method being different from the first method and generating a second sequence of second power estimates.