37.4603GPPIuant interface: General aspects and principlesRelease 16TS
5.1 Physical layer functions
The physical layer provides a multi drop broadcast link between the primary device (RAN Node) and all secondary devices (RET antennas or TMAs). Any message transmitted will be received by all other devices. If two devices transmit at the same time, their messages will be garbled.
The connection requires a half duplex communication, which requires an appropriate scheme for the timing and access control of the connection.
5.2 Data link layer functions
The data link layer provides:
– A data packet communication format;
– An addressing scheme;
– A master/slave relationship whereby the primary device controls the half duplex timing;
– A message checksum scheme to protect from transmission errors;
– A message sequence numbering scheme which protects layer 7 from:
– Duplicated messages;
– Deleted messages;
– Receiving messages in the wrong order.
– A flow control mechanism protecting each device from being overrun by messages.
These functions provide layer 7 with a safe full-duplex connection between the primary device and any secondary device. This full duplex connection allows both the primary and secondary device to transmit layer 7 messages to the opposite device of the connection, whenever they need to. Actual delivery time on layer 2 will depend on the layer 2 polling frequency, which is chosen by the primary device.
5.3 Application layer functions
The list of functions on the Iuant interface is the following:
– Control of RET antennas;
– Application software and configuration data download;
– Alarm Reporting;
– Operator specific data storage;
– Control of Tower Mounted Amplifiers (TMAs).
5.3.1 Control of RET antennas
A RET device provides means to adjust the electrical tilt of one or multiple antennas. The set of procedures to control RET antennas provides means to control the electrical tilt of one or more RET antennas remotely. The procedures are defined in TS 37.466 .
5.3.2 Application software and configuration data download
The interface provides means for downloading new application software and configuration data to a secondary device.
The support of application software download to a secondary device is optional. If a secondary device supports application software download, it shall reset itself and start running the new application software automatically after the completed download. Further details on the software download procedure (e.g. the different states of the secondary device and the supported elementary procedures in these states) are described in subclause 6.1 of TS 37.466 .
5.3.3 Alarm reporting
The secondary device reports every change in error status after subscription for alarm reporting by transmitting alarm messages to the primary device. Alarm information can also be interrogated in the application layer.
5.3.4 Operator specific data storage
The secondary device provides means for storage of operator specific data, e.g. inventory information.
5.3.5 Control of Tower Mounted Amplifiers (TMAs)
The TMA device provides means to indicate alarms and optionally to adjust the gain of TMAs. The set of procedures to control TMAs are defined in TS 37.466 .