What is AISG?

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- everything RF

Jun 10, 2020

The Antenna Interface Standards Group (AISG) is a non-profit international consortium that creates and maintains standards for the control and monitoring of interface between a base station and a variety of tower-top equipment. These include antennas with remote electrical tilt (RET), tower-mounted amplifiers, Remote Radio Heads and a variety of sensors that are used to monitor the operation of tower-top equipment. This consortium has been formed by the collaboration between communication infrastructure manufacturers and network operators. The consortium has till now released four versions of its base communication standard, which are: AISG v1.0, AISG v1.1, AISG v2.0 and AISG v3.0. However, only v3.0 and v2.0 are operational now.

The latest version of the standards (AISG v3.0) provides devices with multiple control ports that may each be connected to different controllers (usually base stations), as well as the ability for the controller to map the RF system interconnections between devices connected to the bus. The standard comprises the base standard together with standards for each subunit type.

AISG v3.0

AISG v3.0 specifies the interface between a primary, typically a base station, and antenna line devices (ALDs) which are manageable units, usually associated with base station antenna systems. ALDs include one or more subunits of different subunit types such as RET, TMA, and antenna sensors. An ALD may have one or more AISG interfaces to be controlled by one or more primaries. Therefore, AISG v3.0 defines two different types of ALDs, which are termed Single-primary ALDs (SALD) and Multi-primary ALDs (MALD). An ALD contained within an enclosure shall provide only one UniqueID. An enclosure containing more than one ALD is not allowed.

AISG v3.0 is divided into this base standard and several subunit type standards. This standard describes the common behavior of antenna line devices with AISG interfaces. Type-specific functionality is defined in separate subunit type standards.

This standard defines the common behavior of ALDs. It also specifies some recommended and some mandatory behavior of the primary.

The v3.0 has been produced by the Antenna Interface Standards Group (AISG) to introduce and define new features and enhancement of the management system for antenna line devices (ALDs) with remote control and monitoring facilities.

New functions introduced in this version of the standard include the discovery of RF cable connections and device interconnections, site mapping capabilities, and the functionality necessary to control an ALD from more than one primary. These functions adhere to the AISG interoperability requirements. This standard is independent of previous 3GPP specifications and provides a complete description of all layers of the protocol.

New features of AISG v3.0 include: 

1. Platform: This platform supports modern complex base station sites and provides easy fault finding in the field. 

2. Improved Specification: Differing AISG v2 implementations have shown the need for more detailed specifications. AISG v3.0 includes:

  • Definitions for the primary requirements
  • Extensive precise pseudocode to ensure uniform implementation by different vendors
  • Much improved document structure

3. Multi-primary support: This feature includes the capability to set the access rights of each of the connected primaries to each of the subunits contained within the ALD.

4. Site Mapping: Site Mapping provides a set of commands that allows the primary to discover the relationships between ALDs present on the AISG bus, their capabilities and their internal connections. It enables the primary to discover details such as:

  • Which RET controls each logical array within an antenna
  • Frequency ranges supported by logical arrays within an antenna
  • RF port connections to logical array(s) within an antenna
  • Relationships between sensors and logical arrays within an antenna
  • Relationships between base station RF ports and connected logical arrays within an antenna
  • The relationship between RF paths and controlled subunits, such as RETs and TMAs.

5. Ping: An optional feature called Ping enables the automatic discovery of RF cable connections between ALDs and base station radios. It also enables the operators to identify RF cables that are incorrectly connected or missing.

6. Enhanced interoperability Testing: The experience of AISG v2 shows that interoperability testing (IOT) needed to be improved. AISG v3.0 standards contain commands and hardware testing definitions to facilitate IOT to improve the quality of testing. These features ensure the devices adhere to the AISG v3.0 standards.

Click here to read the complete specification.

Backward Compatibility with AISG v2

This standard (v3.0) provides tools that enable ALD vendors to build ALDs that share a bus with equipment supporting AISG v2. AISG v3.0 ALDs may be made to switch to AISG v2 mode where they can be controlled by AISG v2 primaries. AISG v3.0 ALDs operating in v3.0 mode can be used on the same bus as AISG v2 ALDs provided that the primary supports this. 

Pure v2 operation is achieved by building support for AISG v2 protocol into AISG v3.0 ALDs and primaries. The v3.0 standard provides tools and methods that enable the equipment to change between AISG v2 and AISG v3.0 mode in a controlled fashion. 

Mixed bus operation can be achieved by separately polling v2 and v3.0 devices on a bus.

The following AISG v3.0 functionality is not available in AISG v2 mode:

- Site Mapping

- Ping functionality

- MALD setup

MALD operation is not defined in AISG v2. MALDs supporting AISG v3.0 can be controlled by AISG v2 primaries but will have limited functionality.

AISG v2.0

It defines a standard data interface at an antenna line device through which functional parameters of the device can be remotely controlled; specifically, it defines the requirements of a three-layer protocol model.

Antenna line devices may include RET antennas, TMAs, boosters, VSWR measuring units, and other tower-top equipment. All these (and others) can be implemented using the system described in this standard, but each device type (kind of equipment) needs a separate definition according to its control and monitoring requirements. This standard is applicable to equipment designed for operation in any type of mobile radio fixed infrastructure.

The reason behind the launch of v3.0 is due to multiple drawbacks of v2.0 that have already been discussed above. For a quick recap, the disadvantages of v2.0 are listed below.

  • Low interoperability testing (IOT)
  • No site mapping
  • No ping functionality
  • No MALD setup

Other versions of AISG such as v1.0, v1.1, etc have been discontinued as they are not fit to use with current devices.

A detailed analysis of AISG v2.0 and v3.0 can be found in the document prepared by the AISG consortium. Click on the link provided below to read more information.