Low latency synchronization scheme for wireless OFDMA systems
AssigneeMediatek Inc.
InventorsYu-Hao Chang, Pei-Kai Liao
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Abstract
In advanced wireless OFDMA communication systems, hierarchical synchronization is adopted to synchronize between a base station (BS) and a mobile station (MS). In a hierarchical synchronization architecture, primary advanced preamble (PA-Preamble) is used for coarse time domain synchronization while cell ID is detected using several accumulated secondary advanced preambles (SA-Preambles). Network entry latency can be reduced by adjusting the relative location of superframe header (SFH), PA-Preamble and SA-Preambles within a superframe. Three different synchronization channel (SCH) architectures are proposed to provide different tradeoffs between network entry latency and the robustness of SA-Preamble design and cell ID detection.
Claims21
A method for downlink synchronization in a cellular orthogonal frequency division multiple access (OFDMA) system, the method comprising:
- allocating a primary advanced preamble (PA Preamble) in a PA frame in an OFDM superframe having a plurality of frames, wherein the PA frame is one of the plurality of frames other than a first frame along time domain;
- allocating one or more secondary advanced preambles (SA Preambles) within the superframe, wherein the one or more SA Preambles are allocated in the plurality of frames other than the PA frame;
- and
- transmitting the OFDM superframe by a base station, wherein the OFDM superframe further comprises a superframe header (SFH) that is located in the first frame of the OFDM superframe along time domain.
A base station in a cellular orthogonal frequency division multiple access (OFDMA) system, the base station comprising:
- a channel allocation module that allocates a primary advanced preamble (PA Preamble) and a plurality of secondary advanced preambles (SA Preambles) in an OFDM superframe, wherein the PA Preamble is allocated in a PA frame that is different from a first frame along time domain within the superframe, and wherein each SA Preamble is allocated in a corresponding frame that is different from the PA frame within the superframe;
- and
- a transmitter that transmits the OFDM superframe, wherein the superframe further comprises a superframe header (SFH) that is located in the first frame of the OFDM superframe along time domain.
A method for downlink synchronization in a cellular orthogonal frequency division multiple access (OFDMA) system, the method comprising:
- allocating a superframe header (SFH) in a first frame of a OFDM superframe having a plurality of frames in time domain, wherein the superframe has a superframe length in time domain;
- allocating a Primary Advanced Preamble (PA Preamble) and one or more Secondary Advanced Preambles (SA Preambles) in each frame of the superframe;
- and
- transmitting the superframe to a mobile station, wherein the PA preamble and the one or more SA Preambles are arranged in a way such that the mobile station takes less than the superframe length to decode the SFH after decoding the PA Preamble.
Dependencies are inferred from the claim text.