Time synchronization using markers

A computing device for a first radio node, said computing device comprising:

• at least one processor;
• and
• at least one memory storing instructions to be executed by the processor, wherein the at least one memory and the instructions are configured to, with the at least one processor, cause the computing device at least to:
• perform first receive-side and transmit-side time measurements in the first radio node for obtaining at least one first time delay between a time start pulse of a clock of the first radio node and at least one marker of a transmit-side marker signal of the first radio node and at least one second time delay between the time start pulse of the clock of the first radio node and at least one marker of a receive-side marker signal of the first radio node, wherein the transmit-side marker signal is generated by assigning a first value for one or more sections of a transmit-side envelope signal exceeding or falling below a pre-defined transmit-side threshold for defining one or more markers and assigning a different value for other sections of the transmit-side envelope signal and the receive-side marker signal is generated by assigning a second value for one or more sections of a receive-side envelope signal exceeding or falling below a pre-defined receive-side threshold for defining one or more markers and assigning a different value for other sections of the receive-side envelope signal, the transmit-side and receive-side envelope signals being generated by taking an envelope of sampled transmit and receive signals of the first radio node;
• receive or retrieve information on at least one third time delay between a time start pulse of a clock of the second radio node and at least one marker of a transmit-side marker signal of the second radio node and at least one fourth time delay between the time start pulse of the clock of the second radio node and at least one marker of a receive-side marker signal of the second radio node;
• calculate a time difference between the first and second radio nodes based on the at least one first, second, third and fourth time delays;
• and
• synchronize or correct existing synchronization between the clocks of the first and second radio nodes by adjusting of the clock of the first radio node based on the time difference and/or transmitting information on the time difference from the first radio node to the second radio node for adjusting the clock of the second radio node.

A method, comprising:

• performing, in a first radio node, first receive-side and transmit-side time measurements for obtaining at least one first time delay between a time start pulse of a clock of the first radio node and at least one marker of a transmit-side marker signal of the first radio node and at least one second time delay between the time start pulse of the clock of the first radio node and at least one marker of a receive-side marker signal of the first radio node, wherein the transmit-side marker signal is generated by assigning a first value for one or more sections of a transmit-side envelope signal exceeding or falling below a pre-defined transmit-side threshold for defining one or more markers and assigning a different value for other sections of the transmit-side envelope signal and the receive-side marker signal is generated by assigning a second value for one or more sections of a receive-side envelope signal exceeding or falling below a pre-defined receive-side threshold for defining one or more markers and assigning a different value for other sections of the receive-side envelope signal, the transmit-side and receive-side envelope signals being generated by taking an envelope of sampled transmit and receive signals of the first radio node;
• receiving or retrieving, by the first radio node from a second radio node, information on at least one third time delay between a time start pulse of a clock of the second radio node and at least one marker of a transmit-side marker signal of the second radio node and at least one fourth time delay between the time start pulse of the clock of the second radio node and at least one marker of a receive-side marker signal of the second radio node;
• calculating, by the first radio node, a time difference between the first and second radio nodes based on the at least one first, second, third and fourth time delays;
• and
• synchronizing or correcting, by the first radio node, an existing synchronization between the clocks of the first and second radio nodes by adjusting of the clock of the first radio node based on the time difference and/or transmitting information on the time difference from the first radio node to the second radio node for adjusting the clock of the second radio node.

A method comprising:

• sampling transmit and receive signals of a first radio node to be transmitted to or received from a second radio node;
• producing a transmit-side envelope signal based on a sampled transmit signal;
• generating, based on the transmit-side envelope signal, a transmit-side marker signal by assigning a first value for one or more sections of the transmit-side envelope signal exceeding or falling below a pre-defined transmit-side threshold for defining one or more markers and assigning a different value for other sections of the transmit-side envelope signal;
• measuring at least one first time delay between at least one time start pulse of a clock of the first radio node and at least one marker of the transmit-side marker signal;
• storing to a memory and/or outputting said at least one first time delay;
• producing a receive-side envelope signal based on a sampled receive signal;
• generating, based on the receive-side envelope signal, a receive-side marker signal by assigning a second value for sections of the receive-side envelope signal exceeding or falling below a pre-defined receive-side threshold value for defining one or more markers and assigning a different value for other sections of the receive-side envelope signal;
• measuring at least one second time delay between the at least one time start pulse of the clock of the first radio node and at least one marker of the receive-side marker signal;
• and
• storing to the memory and/or outputting said at least one second time delay.

A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to at least:

• perform first receive-side and transmit-side time measurements in a first radio node for obtaining at least one first time delay between a time start pulse of a clock of the first radio node and at least one marker of a transmit-side marker signal of the first radio node and at least one second time delay between the time start pulse of the clock of the first radio node and at least one marker of a receive-side marker signal of the first radio node, wherein the transmit-side marker signal is generated by assigning a first value for one or more sections of a transmit-side envelope signal exceeding or falling below a pre-defined transmit-side threshold for defining one or more markers and assigning a different value for other sections of the transmit-side envelope signal and the receive-side marker signal is generated by assigning a second value for one or more sections of a receive-side envelope signal exceeding or falling below a pre-defined receive-side threshold for defining one or more markers and assigning a different value for other sections of the receive-side envelope signal, the transmit-side and receive-side envelope signals being generated by taking an envelope of sampled transmit and receive signals of the first radio node;
• receive or retrieve information on at least one third time delay between a time start pulse of a clock of the second radio node and at least one marker of a transmit-side marker signal of the second radio node and at least one fourth time delay between the time start pulse of the clock of the second radio node and at least one marker of a receive-side marker signal of the second radio node;
• calculate a time difference between the first and second radio nodes based on the at least one first, second, third and fourth time delays;
• and
• synchronize or correct existing synchronization between the clocks of the first and second radio nodes by adjusting of the clock of the first radio node based on the time difference and/or transmitting information on the time difference from the first radio node to the second radio node for adjusting the clock of the second radio node.

A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least a method comprising:

• transmitting or receiving sampling transmit and receive signals of a first radio node to or from a second radio node;
• producing a transmit-side envelope signal based on a sampled transmit signal;
• generating, based on the transmit-side envelope signal, a transmit-side marker signal by assigning a first value for one or more sections of the transmit-side envelope signal exceeding or falling below a pre-defined transmit-side threshold for defining one or more markers and assigning a different value for other sections of the transmit-side envelope signal;
• measuring at least one first time delay between at least one time start pulse of a clock of the first radio node and at least one marker of the transmit-side marker signal;
• storing to a memory and/or outputting said at least one first time delay;
• producing a receive-side envelope signal based on a sampled receive signal;
• generating, based on the receive-side envelope signal, a receive-side marker signal by assigning a second value for sections of the receive-side envelope signal exceeding or falling below a pre-defined receive-side threshold value for defining one or more markers and assigning a different value for other sections of the receive-side envelope signal;
• measuring at least one second time delay between the at least one time start pulse of the clock of the first radio node and at least one marker of the receive-side marker signal;
• and
• storing to the memory and/or outputting said at least one second time delay.