Method and system for downlink synchronization in wireless networks

A system base station in a wireless communication system, the base station comprising:

• a transceiver;
• and
• at least one processor coupled with the transceiver and configured to:
• generate a plurality of synchronization signals based on a pseudorandom sequence,
• map the plurality of synchronization signals in delay-Doppler (DD) to determine a two-dimensional delay Doppler resource block (DDRB),
• transform the mapped synchronization signals to time-frequency (TF) domain to obtain a hybrid frame associated with the plurality of synchronization signals,
• generate a downlink frame by transforming the hybrid frame from the TF domain to a time domain, and
• transmit the downlink frame to a terminal for performing downlink synchronization.

A method performed by a terminal in a wireless communication system, the method comprising:

• receiving, from a base station, a downlink frame;
• determining a primary synchronization signal (PSS) based on a time domain correlation of the downlink frame with the locally generated PSS using one or more parallel correlators to determine a start position of the received downlink frame and a primary cell identity (PCID) corresponding to the PSS;
• determining a frequency offset based on correlation using the one or more parallel correlators for performing frequency correction on the received downlink frame;
• transforming the frequency corrected received downlink frame in delay-Doppler domain;
• extracting, from the transformed downlink frame in delay-Doppler domain, a secondary synchronization signal (SSS) based on a predefined mapping scheme;
• performing 2D delay-Doppler correlation of the extracted SSS with a locally generated SSS to determine a secondary cell identity (SCID) corresponding to the SSS;
• and
• performing downlink synchronization and cell identity estimation using the determined PSS and the extracted SSS.

A terminal in a wireless communication system, the terminal comprising:

• a transceiver;
• and
• at least one processor coupled with the transceiver and configured to:
• receive, from a base station, a downlink frame,
• determine a primary synchronization signal (PSS) based on a time domain correlation of the downlink frame with the locally generated PSS using one or more parallel correlators to determine a start position of the received downlink frame and a primary cell identity (PCID) corresponding to the PSS,
• determine a frequency offset based on correlation using the one or more parallel correlators for performing frequency correction on the received downlink frame,
• transform the frequency corrected received downlink frame in delay-Doppler domain,
• extract, from the transformed downlink frame in delay-Doppler domain, a secondary synchronization signal (SSS) based on a predefined mapping scheme,
• perform 2D delay-Doppler correlation of the extracted SSS with a locally generated SSS to determine a secondary cell identity (SCID) corresponding to the SSS, and
• perform downlink synchronization and cell identity estimation using the determined PSS and the extracted SSS.