Adaptive selection of signal-detection mode

A signal and synchronization signal technology, applied in wireless communication, digital transmission system, electrical components, etc., can solve the problem of increasing the calculation burden of the synchronization process

Active Publication Date: 2019-02-12
TELEFON AB LM ERICSSON (PUBL)
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Problems solved by technology

[0010] It should be appreciated that searching across multiple frequency hypotheses, in addition to across multiple time offsets, has a multiplicative effect on the number of hypotheses that must be tested, and thus increases the computational burden of the synchronization process

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  • Adaptive selection of signal-detection mode
  • Adaptive selection of signal-detection mode
  • Adaptive selection of signal-detection mode

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Embodiment Construction

[0019] So-called coherent detection is often used to detect the presence of synchronization signals in the received signal. With coherent detection, the phases of all samples / symbols are considered jointly, since all samples / symbols over a given time period are effectively added constructively / coherently in the received signal processing. For example, coherent detection may be performed by correlating a time series of complex-valued samples taken from the received signal with a reference sequence corresponding to the synchronization signal as represented in the time domain.

[0020] Conventional coherent detection does not tolerate frequency errors well because frequency errors deviate samples in the time-domain sequence, eg over time, from a reference sequence that was initially time-aligned and phase-aligned with the time-domain sequence. Thus, when using coherent detection techniques, it is generally necessary to add a frequency offset search dimension to the synchronizatio...

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Abstract

A wireless device detects a synchronization signal by obtaining (210), from a received signal, a sequence of samples, and calculating (220) a differentially decoded sequence from the obtained sequenceof samples. The wireless device correlates (230) the calculated differentially decoded sequence with a first reference sequence corresponding to the synchronization signal, at each of a plurality oftime offsets, and identifies which of the plurality of time offsets results in a largest correlation result. In response to determining (240) that the largest correlation result does not meet a predetermined reliability criterion, the wireless device correlates (250) the obtained sequence of samples with a second reference sequence, at each of a plurality of time and frequency offsets, and identifies which combination of time offset and frequency offset results in a largest correlation result. The first reference sequence comprises a differentially decoded version of the second reference sequence.

Description

technical field [0001] The present disclosure relates generally to wireless communications and, more particularly, to techniques and apparatus for detecting time and frequency offsets to synchronization sequences in received signals. Background technique [0002] In order to establish a communication link between two wireless devices, a wireless device receiving a signal transmitted by another wireless device must synchronize receiver processing with the received signal. Both time synchronization and frequency synchronization are required for optimal demodulation and decoding of the information carried by the received signal. This time synchronization and frequency synchronization can then be applied to the signals transmitted by the wireless device. For example, time synchronization and frequency synchronization are necessary for a wireless device (often called user equipment or "UE" in industry jargon) to access a wireless network, regardless of the random access (RA) pro...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
CPCH04W56/0055H04L27/0014H04L2027/0026H04L27/2657H04L27/2663H04L27/2278H04L27/2331
Inventor A.瑞尔J.阿克斯纳J.鲁内H.萨琳
Owner TELEFON AB LM ERICSSON (PUBL)
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