Abstract: A method (10) of encapsulating digital communications signals for transmission on a communications link, comprising steps: a. receiving a first signal of a first signal type and comprising a first clock signal and receiving a second signal of a second signal type, different to the first, and comprising a second clock signal different to the first clock signal, each clock signal having a respective clock value and accuracy (12); b. obtaining the first clock signal (14); c. obtaining a difference between at least one of the clock values of the clock signals and the accuracies of the clock signals (16) and buffering the second signal for a time at least long enough to compensate for the difference (18); and d. assembling the first signal and the buffered second signal into a frame comprising an overhead and a payload comprising a first portion and a second portion, mapping the first signal into the first portion and the second signal into the second portion (20), wherein step d.

Abstract: A transport network (20) is connected to a first wireless base station (3, 4) and to a second wireless base station (6). The first wireless base station comprises a remote radio unit (3) and a baseband processing unit (4) which are connected by the transport network (20). A node (16) of the transport network (20) receives a synchronous time division multiplexed communication signal which carries at least a first communication signal between the baseband processing unit (4) and the remote radio unit (3). The node (16) determines a frequency synchronisation signal from the synchronous time division multiplexed communication signal. The node (16) transmits the synchronous time division multiplexed communication signal to the remote radio unit (3) of the first wireless base station. The node (16) transmits the frequency synchronisation signal to the second wireless base station (6). The node (16) also assists with providing phase/time synchronisation to the second wireless base station (6).

Abstract: A network node (30) for a radio access network, wherein the network node comprises a switch system (35) configured to switch traffic for a plurality of base stations (3, 5; 8) of the radio access network. The switch system (35) is configured to provide for communication between a remote radio unit (3) and a baseband processing unit (5, 12) of the said plurality of base stations. The switch system (35) is configured to provide for communication between a first base station (8) and a second base station (3, 5) of said plurality of base stations. At least one of the first or second base station is a radio base station (8) comprising baseband processing.

Abstract: A transport network (20) is connected to a first wireless base station (3, 4) and to a second wireless base station (6). The first wireless base station comprises a remote radio unit (3) and a baseband processing unit (4) which are connected by the transport network (20). A node (16) of the transport network (20) receives a synchronous time division multiplexed communication signal which carries at least a first communication signal between the baseband processing unit (4) and the remote radio unit (3). The node (16) determines a frequency synchronisation signal from the synchronous time division multiplexed communication signal. The node (16) transmits the synchronous time division multiplexed communication signal to the remote radio unit (3) of the first wireless base station. The node (16) transmits the frequency synchronisation signal to the second wireless base station (6). The node (16) also assists with providing phase/time synchronisation to the second wireless base station (6).

Abstract: A method for switching data signals transmitted over a transport network is disclosed. The method comprises receiving a plurality of input data signals of a first signal type wherein the plurality of data signals of the first signal type comprises data signals exchanged between a Radio Equipment and a Radio Equipment Controller and aggregating the plurality of input data signals into an aggregated first data signal. The method also comprises receiving a second data signal of a second signal type different to the first signal type, and multiplexing the first data signal with the second data signal to form a combined data signal. The method further comprises forwarding the combined data signal to the transport network. Multiplexing the first data signal with the second data signal comprises, for a frame of the combined data signal, allocating the first data signal to a portion of the frame reserved for the first data signal, and allocating the second data signal to a remaining portion of the frame.

Abstract: A method (10) of encapsulating digital communications traffic for transmission on an optical link, the method comprising: a. receiving an input digital communications signal having an input line code (12); b. performing clock and data recovery on the input digital communications signal to obtain input line coded digital communications traffic and a recovered clock signal (14); c. decoding the input digital communications traffic to obtain information bits and non-information bits (16); d. removing the non-information bits (18); e. adding service channel bits for monitoring or maintenance (20); f. assembling the service channel bits and information bits into frames (22); and g. line coding the assembled frames using an output line code to form an encapsulated digital communications signal for transmission on an optical link (24), wherein steps c. to g. are performed using the timing of the recovered clock signal. A communications network receiver configured to implement the method is also provided.

Abstract: Techniques are disclosed for determining propagation delay of a first path and or of a second path which connect a first transceiver unit associated with a first clock to a second transceiver unit associated with a second clock in a communications network, based on a first time reference representing a time of transmission of a first signal from the first transceiver unit, a second time reference representing the time of receipt of the first signal at the second transceiver unit, a third time reference representing a time of transmission of a reply to the second signal from the second transceiver unit, and a fourth time reference representing the time of receipt of the reply to the second signal at the first transceiver unit.

Abstract: A transport network (20) is connected to a first wireless base station (3, 4) and to a second wireless base station (6). The first wireless base station comprises a remote radio unit (3) and a baseband processing unit (4) which are connected by the transport network (20). A node (16) of the transport network (20) receives a synchronous time division multiplexed communication signal which carries at least a first communication signal between the baseband processing unit (4) and the remote radio unit (3). The node (16) determines a frequency synchronisation signal from the synchronous time division multiplexed communication signal. The node (16) transmits the synchronous time division multiplexed communication signal to the remote radio unit (3) of the first wireless base station. The node (16) transmits the frequency synchronisation signal to the second wireless base station (6). The node (16) also assists with providing phase/time synchronisation to the second wireless base station (6).

Abstract: A network node (30) for a radio access network, wherein the network node comprises a switch system (35) configured to switch traffic for a plurality of base stations (3, 5; 8) of the radio access network. The switch system (35) is configured to provide for communication between a remote radio unit (3) and a baseband processing unit (5, 12) of the said plurality of base stations. The switch system (35) is configured to provide for communication between a first base station (8) and a second base station (3, 5) of said plurality of base stations. At least one of the first or second base station is a radio base station (8) comprising baseband processing.

Abstract: A method for switching data signals transmitted over a transport network is disclosed. The method comprises receiving a plurality of input data signals of a first signal type wherein the plurality of data signals of the first signal type comprises data signals exchanged between a Radio Equipment and a Radio Equipment Controller and aggregating the plurality of input data signals into an aggregated first data signal. The method also comprises receiving a second data signal of a second signal type different to the first signal type, and multiplexing the first data signal with the second data signal to form a combined data signal. The method further comprises forwarding the combined data signal to the transport network. Multiplexing the first data signal with the second data signal comprises, for a frame of the combined data signal, allocating the first data signal to a portion of the frame reserved for the first data signal, and allocating the second data signal to a remaining portion of the frame.

Abstract: A method and apparatus for determining propagation delay of a first path and or of a second path which connect a first transceiver unit associated with a first clock to a second transceiver unit associated with a second clock in a communications network. The apparatus comprises a control unit configured to cause the first transceiver unit to transmit a first signal to the second transceiver unit over the first path and to receive a reply to the first signal from the second transceiver unit over the second path, and to transmit a second signal to the second transceiver unit over the second path and to receive a reply to the second signal from the second transceiver unit over the first path.

Abstract: A method of configuring transmission wavelengths in a passive optical network comprising a wavelength selective routing element between first and second locations. The method comprises: at a first location: a. iteratively generating and transmitting a first optical signal at different ones of a plurality of wavelengths until a second optical signal is received at the first location; and then b. ceasing transmission of the first optical signal and then recommencing transmission of the first optical signal at the wavelength being transmitted when the second optical signal was received; and at a second location, remote from the first location: c. waiting until the first optical signal is received at the second location; d. iteratively generating and transmitting the second optical signal at different ones of a plurality of wavelengths until the first optical signal is no longer received at the second location; and e.

Abstract: A method (10) of encapsulating digital communications signals for transmission on a communications link, comprising steps: a. receiving a first signal of a first signal type and comprising a first clock signal and receiving a second signal of a second signal type, different to the first, and comprising a second clock signal different to the first clock signal, each clock signal having a respective clock value and accuracy (12); b. obtaining the first clock signal (14); c. obtaining a difference between at least one of the clock values of the clock signals and the accuracies of the clock signals (16) and buffering the second signal for a time at least long enough to compensate for the difference (18); and d. assembling the first signal and the buffered second signal into a frame comprising an overhead and a payload comprising a first portion and a second portion, mapping the first signal into the first portion and the second signal into the second portion (20), wherein step d.

Abstract: A method (10) of encapsulating digital communications traffic for transmission on an optical link, the method comprising: a. receiving an input digital communications signal having an input line code (12); b. performing clock and data recovery on the input digital communications signal to obtain input line coded digital communications traffic and a recovered clock signal (14); c. decoding the input digital communications traffic to obtain information bits and non-information bits (16); d. removing the non-information bits (18); e. adding service channel bits for monitoring or maintenance (20); f. assembling the service channel bits and information bits into frames (22); and g. line coding the assembled frames using an output line code to form an encapsulated digital communications signal for transmission on an optical link (24), wherein steps c. to g. are performed using the timing of the recovered clock signal. A communications network receiver configured to implement the method is also provided.

Abstract: A method and apparatus for determining propagation delay of a first path and or of a second path which connect a first transceiver unit associated with a first clock to a second transceiver unit associated with a second clock in a communications network. The apparatus comprises a control unit configured to cause the first transceiver unit to transmit a first signal to the second transceiver unit over the first path and to receive a reply to the first signal from the second transceiver unit over the second path, and to transmit a second signal to the second transceiver unit over the second path and to receive a reply to the second signal from the second transceiver unit over the first path.

Abstract: A method of configuring transmission wavelengths in a passive optical network comprising a wavelength selective routing element between first and second locations. The method comprises: at a first location: a. iteratively generating and transmitting a first optical signal at different ones of a plurality of wavelengths until a second optical signal is received at the first location; and then b. ceasing transmission of the first optical signal and then recommencing transmission of the first optical signal at the wavelength being transmitted when the second optical signal was received; and at a second location, remote from the first location: c. waiting until the first optical signal is received at the second location; d. iteratively generating and transmitting the second optical signal at different ones of a plurality of wavelengths until the first optical signal is no longer received at the second location; and e.