Method for adding leaf node to multi-node base station
View Patent ↗Adding a new subsystem node to a multi-node base station topology (e.g., a chain or tree topology) in a telecommunications network can disrupt the effective operation of the existing multi-node base station. By accurately measuring the timing difference between uplink and downlink signaling across a current terminating node during the configuration of the new terminating node, the new node can be added with reduced impact upon the operation of the existing base station nodes.
1. A method for dynamically adding a leaf node to a multi-node base station system having at least one control node and at least one active radio access node, the radio access node having a first lane for receiving data from the control node and transmitting further data to the control node, the method comprising:
enabling a second lane in the radio access node, the second lane being coupled to a lane of the leaf node;
in the radio access node, measuring a frame timing difference between the receive timing in an uplink from the leaf node and receive timing in a downlink;
establishing synchronization between the control node and the leaf node using the measured frame timing difference;
setting user plane data parameters for the leaf node, thereby initiating transmission of user data to the leaf node; and
selecting a subchannel for use in communicating instructions to the leaf node, including selecting a unique node identifier, and calculating a unique subchannel value as a function of the node identifier.
2. The method of claim 1 , wherein the step of selecting a subchannel further comprises:
assigning a predetermined first subchannel value to the leaf node; and
assigning a second subchannel value to the radio access node, the second subchannel value being different from the first subchannel value.
3. The method of claim 1 , wherein the step of establishing synchronization comprises:
transmitting the frame timing difference to the control node;
calculating a transmission timing offset for the leaf node; and
transmitting the calculated transmission timing offset to the leaf node using the selected subchannel.
4. A node in a multi-node base station system having at least one control node, the node being in communication with the control node, wherein the node comprises:
a first lane comprising:
a first receiver unit for receiving downlink data from the control node in at least one first container;
a first transmitter unit, including a transmission framer, for transmitting uplink data to the control node;
a first timer operable to route timings to the first transmitter unit;
a networking interface; and
a code word filter unit for forwarding data corresponding to a selected subset of code words;
a second lane, forming a master port in communication with a leaf node, the second lane comprising:
a second receiver unit for receiving uplink data from the leaf node;
a second transmitter unit, including a transmission framer, for transmitting downlink data to the leaf node;
a second timer operable to route timings to the second transmitter unit;
a second networking interface; and
a second code word filter unit for forwarding data corresponding to a selected subset of code words; and
a timing difference calculator for establishing the timing difference between receive and transmit paths in the respective lanes of the node,
wherein the timing difference calculator comprises:
a basic frame difference calculator that calculates the timing difference between receive and transmit paths in units of basic frames;
a hyper frame difference calculator that calculates the timing difference between receive and transmit paths in units of hyper frames; and
a multiplexer that increments an output of the hyper frame timing difference calculator when a rollover condition is detected in the basic frame difference calculator.
5. A method for adding a terminating node in a Common Public Radio Interface (CPRI) chain having at least one active networking node, the networking node having at least a first lane and a second lane, the method comprising:
enabling the second lane in the networking node;
instructing the terminating node to set up;
receiving a power up acknowledgement message from the networking node for establishing synchronization between the networking node and the terminating node;
calculating a timing difference between the receive timing in an uplink from the terminating node and receive timing in a downlink;
reporting the timing difference to a radio equipment controller (REC) node;
establishing synchronization between the REC node and the terminating node using the measured timing difference;
setting user plane data parameters for the terminating node thereby facilitating the reception of user plane data from the terminating node; and
selecting a subchannel for use in communicating instructions to the terminating node, including selecting a unique node identifier, and calculating a unique subchannel value as a function of the node identifier.
6. The method of claim 5 , wherein the networking node is a radio equipment (RE) node or a radio equipment controller (REC) node.