Method and apparatus for synchronization in an OFDM wireless communication network
A method and apparatus for synchronization in an orthogonal frequency division multiplexing (OFDM) network is disclosed. A wireless transmit/receive unit (WTRU) is configured to receive a primary synchronization signal and a secondary synchronization signal from a cell. The primary synchronization signal and the secondary synchronization signal are spaced by a known number of OFDM symbols. The primary synchronization signal and the secondary synchronization signal are received in a same number of subcarriers in their respective OFDM symbol. A location of at least the secondary synchronization signal in the system bandwidth is variable.
1. A wireless transmit/receive unit (WTRU) comprising:
a receiver; and
a processor;
wherein a location of at least a secondary sychronization signal in a system bandwidth is variable,
wherein the receiver and the processor are configured to receive a primary synchronization signal and the secondary synchronization signal from a cell having the system bandwidth,
wherein the primary synchronization signal and the secondary synchronization signal are separated in time by a known number of orthogonal frequency division multiplexing (OFDM) symbols,
wherein the primary synchronization signal and the secondary synchronization signal are received in a same number of subcarriers in their respective OFDM symbol, and
wherein a plurality of subcarriers adjacent to and on both sides of the secondary synchronization signal and in a same OFDM symbol are set to zero, and a different plurality of subcarriers on the both sides of the secondary synchronization signal and in the same OFDM symbol include data.
2. The WTRU of claim 1 , wherein the processor is further configured to determine a cell identifier from the received primary synchronization signal and the received secondary synchronization signal.
3. The WTRU of claim 1 , wherein the processor is further configured to determine a cell timing based on the received primary synchronization signal and the received secondary synchronization signal.
4. The WTRU of claim 1 , wherein the primary synchronization signal and the secondary synchronization signal are received in a same number of subcarriers over an entire bandwidth.
5. The WTRU of claim 1 , wherein the separation in time of the primary synchronization signal and the secondary synchronization signal is at least one OFDM symbol.
6. The WTRU of claim 1 , wherein the both sides of the secondary synchronization signal comprise subcarriers that are in a higher frequency range than subcarriers of the secondary synchronization signal and subcarriers that are in a lower frequency range than subcarriers of the secondary synchronization signal.
7. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising:
receiving a primary synchronization signal from a cell having a system bandwidth and a secondary synchronization signal from the cell such that the secondary synchronization signal has a location in the system bandwidth that is variable, wherein the primary synchronization signal and the secondary synchronization signal are separated in time by a known number of orthogonal frequency division multiplexing (OFDM) symbols, wherein the primary synchronization signal and the secondary synchronization signal are received in a same number of subcarriers in their respective OFDM symbol, and wherein a plurality of subcarriers adjacent to and on both sides of the secondary synchronization signal and in a same OFDM symbol are set to zero, and a different plurality of subcarriers on the both sides of the secondary synchronization signal and in the same OFDM symbol include data.
8. The method of claim 7 , further comprising determining a cell identifier from the received primary synchronization signal and the received secondary synchronization signal.
9. The method of claim 7 , further comprising determining a cell timing based on the received primary synchronization signal and the received secondary synchronization signal.
10. The method of claim 7 , wherein the primary synchronization signal and the secondary synchronization signal are received in a same number of subcarriers over an entire bandwidth.
11. The method of claim 7 , wherein the separation in time of the primary synchronization signal and the secondary synchronization signal is at least one OFDM symbol.
12. The method of claim 7 , wherein the both sides of the secondary synchronization signal comprise subcarriers that are in a higher frequency range than subcarriers of the secondary synchronization signal and subcarriers that are in a lower frequency range than subcarriers of the secondary synchronization signal.