Method and device for data streaming in a mobile communication system
Interfacing between radio units in a base station in a mobile communication system uses a common public radio interface CPRI for streaming IQ data samples arranged in lanes. A separate serial interface sRIO is now additionally used for transferring selected data samples arranged in packets, the selected samples corresponding to selected lanes streamed between other radio units via the common public radio interface. In the radio unit, the selected data samples are arranged in packets to be transmitted via the serial interface, and, vice versa, the selected data samples arranged in packets received via the serial interface are arranged in lanes. A system timer coupled to the CPRI generates a timebase for controlling the sRIO interface in order to have it synchronized. Advantageously the data sample transfer capacity of the streaming CPRI interface is extended using the packet based serial interface.
1. A method of interfacing in a base station in a mobile communication system, the base station comprising radio units, different types of the radio units including at least one radio equipment unit coupled to at least one antenna and at least one radio equipment controller unit for controlling the radio equipment unit, the radio units having a common public radio interface for streaming data samples arranged in a plurality of lanes corresponding to antenna signals and a serial rapid input output interface for transferring packets separate from the common public radio interface, the method comprising:
storing, by a direct memory access unit, selected data samples from selected lanes of the plurality of lanes of the streamed data samples in a memory of a first radio unit according to a buffer descriptor, wherein the data samples arranged in the plurality of lanes were streamed from a preceding radio unit to the first radio unit;
transferring, by the direct memory access unit, the selected data samples between the first and a second radio unit, the selected data samples converted to packets of selected data samples by the serial rapid input output interface, the packets of selected data samples corresponding to the selected lanes streamed from the preceding radio unit via the common public radio interface; and
transferring further data samples arranged in further lanes of the plurality of lanes to the first radio unit, the further lanes being streamed from the preceding radio unit via the common public radio interface and are in addition to the selected lanes of the plurality of lanes, wherein the further data samples of the further lanes are processed in the first radio unit and wherein the selected data samples bypass processing in the first radio unit and are transferred to the second radio unit.
2. Method as claimed in claim 1 , wherein the method comprises:
transferring a predetermined amount of the selected data samples for the selected lanes arranged in M packets via the serial rapid input output interface; and
generating and transferring, between the first and second radio unit via the serial rapid input output interface, an interrupt packet after transferring said M packets for the selected lanes.
3. A device, for use in a radio unit, the radio unit coupled to at least one radio equipment unit, the at least one radio equipment unit coupled to at least one antenna and at least one radio equipment controller unit for controlling the radio equipment unit, the device comprising:
a common public radio interface for streaming data samples arranged in a plurality of lanes corresponding to antenna signals and a serial rapid input output interface for converting the streamed data samples to packets of data samples and for transferring the data samples arranged in packets, the serial rapid input output interface separate from the common public radio interface; and
a data handler comprising a direct memory access unit for directly accessing a memory of the device, the data handler arranged for providing a buffer descriptor to the direct memory access unit,
storing selected data samples from selected lanes of the plurality of lanes of the streamed data samples in the memory of the device according to the buffer descriptor, the streamed data samples of the plurality of lanes streamed from a preceding radio unit,
transferring the selected data samples from the memory to the serial rapid input output interface according to the buffer descriptor, and
transferring the selected data samples to a subsequent radio unit, the selected data samples arranged in packets via the serial rapid input output interface, the selected data samples corresponding to selected lanes streamed between the device and the preceding radio unit via the common public radio interface, the selected data samples bypassing processing in the radio unit, and
transferring further data samples arranged in further lanes of the plurality of lanes to the subsequent radio unit, the further lanes streamed from the data samples in addition to the selected lanes, the further data samples of the further lanes are processed in the radio unit.
4. Device as claimed in claim 3 , wherein the data handler is configured for providing the buffer descriptor for respective data buffers corresponding to units of antenna data.
5. Device as claimed in claim 3 , wherein the data handler is configured for maintaining a ring memory for storing buffer descriptors for respective data buffers, the sequence of stored buffer descriptors in the ring memory corresponding to sets of data samples to be transferred as packets.
6. Device as claimed in claim 3 , wherein the data handler is arranged for transferring a predetermined amount of the selected data samples for the selected lanes arranged in M packets via the serial rapid input output interface, and for generating and transferring, to the subsequent radio unit via the serial rapid input output interface, an interrupt packet after transferring said M packets for the selected lanes.
7. Device as claimed in claim 3 , wherein the device is configured for transferring data samples of N lanes to the subsequent radio unit via the common public radio interface, and the device is configured for generating and transferring, to a subsequent radio control device, an interrupt packet after transferring a predetermined amount of the data samples of the N lanes.
8. Device as claimed in claim 3 , wherein the device is arranged for receiving an interrupt packet indicative of transferring, by a preceding radio unit, a predetermined amount of the selected data samples for the selected lanes arranged in M packets via the serial interface, and comprises an interrupt unit for, upon receiving the interrupt packet, triggering processing the selected data samples according to data samples arranged in lanes.
9. Device as claimed in claim 3 , wherein the device is arranged for receiving an interrupt packet indicative of transferring, by a preceding radio unit, a predetermined amount of the data samples of the N lanes, and comprises an interrupt unit for, upon receiving the interrupt packet triggering processing the predetermined amount of the data samples.
10. Device as claimed in claim 3 , wherein the serial rapid input output interface comprises a serial interface controller arranged for formatting data samples in packets to be transmitted, and for retrieving data samples from packets as received.
11. Device as claimed in claim 3 , wherein the device comprises a system timer for generating a common public radio interface timebase for synchronizing the serial rapid input output interface to said timebase.
12. Device as claimed in claim 3 , wherein the data samples arranged in the plurality of lanes corresponding to antenna signals are further arranged in antenna-carrier units.
13. Radio equipment controller unit for a base station in a mobile communication system, the radio equipment controller unit comprising the device according to claim 3 .
14. Radio equipment unit for a base station in a mobile communication system, the radio equipment unit comprising the device according to claim 3 .
15. Integrated circuit comprising the device according to claim 3 .