Transmitter, receiver and methods for transmitting/ receiving synchronisation signals

A method, performed by a transmitter , for transmitting a first type of synchronisation signal in M1 symbols li, 0≦i≦(M1−1) of a subframe and a second type of synchronisation signal in M2 symbols kj, 0≦j≦(M2−1) in the subframe, the method comprising:

• determining in which M1 symbols li of the subframe, the synchronisation signal of the first type is to be transmitted;
• calculating in which M2 symbols kj of the subframe, the synchronisation signal of the second type is to be transmitted by placing the M2 symbols kj at a one or more determined symbol distance from an associated symbol li, wherein said one or more determined symbol distance between each of the M2 symbols kj and the respective associated symbol li is equal between all of the M1 symbols li in the subframe and their respective associated M2 symbols kj;
• and
• transmitting the synchronisation signal of the first type in the determined M1 symbols li of the subframe and the synchronisation signal of the second type in the calculated M2 symbols kj of the subframe, wherein the subframe comprises N symbols with N≧M2≧M1≧2.

A receiver configured to detect a received first type of synchronisation signal, in M1 symbols li, 0≦i≦(M1−1) of a subframe and a second type of synchronisation signal, in M2 symbols kj, 0≦j≦(M2−1), received in a subframe comprising N symbols, wherein N≧M2≧M1≧2, the receiver comprising:

• a receiving circuit configured to receive the synchronisation signal of the first type in the M1 symbols li of the subframe;
• a processor, configured to:
• establish a one or more determined symbol distance between a symbol kj and an associated symbol li, and
• calculate in which M2 symbols kj of the subframe, the synchronisation signal of the second type is to be detected, wherein said one or more determined symbol distance between each of the M2 symbols kj and the respective associated symbol li is equal for all of the M1 symbols li in the subframe, and wherein the subframe comprises N symbols, where N≧M2≧M1≧2.

A method, performed by a receiver, for detecting a first type of synchronisation signal, in M1 symbols li, 0≦i≦(M1−1) of a subframe and a second type of synchronisation signal, in M2 symbols kj, received in the subframe, the method comprising:

• determining in which M1 symbols li of the subframe, the synchronisation signal of the first type is received;
• establishing a one or more determined symbol distance between each of the M2symbols kj and the respective associated symbol li which is equal for all of the M1 symbols li in the subframe;
• calculating in which M2 symbols kj of the subframe , the synchronisation signal of the second type is to be received;
• and
• detecting the M2 synchronisation signal of the second type in the calculated M2 symbols kj of the subframe, wherein the subframe comprises N symbols, where N≧M2≧M1≧2.