Explanation...

The diagram to the left shows a typical wireless AMR/demand control installation.

Two-way Wireless

Not all customers have HFC cable or IP connections. To reach these customers, IES uses licensed VHF wireless. The advantage of using licensed frequencies is that more power can be used, providing more reliability than 900 MHz unlicensed. Municipal utilities have a straightforward and low cost process to get frequencies allocated. Like most wireless systems, the IES system requires repeating units to be deployed in the city. The difference between the IES system and unlicensed systems is the number of repeating units that are required. To cover 5 square miles, 20 – 30 digipeaters would be required, depending on the terrain and conditions. These digipeaters would typically be mounted on street poles. The diagram above shows a typical wireless installation.

The IES C3IWireless gateways use a licensed frequency, typically between 150 and 170 MHz. A frequency must be coordinated by the appropriate frequency coordinator. The communications are FM narrowband and use a bandwidth of 12.5 kHz.

A base station radio operating at 40 watts must be installed on one of the City’s communications towers. An IP connection is required to connect the base station with the IES server. Each IES C3IWireless gateway operates at 120 miliwatts. To ensure coverage through the city, 10-20 digipeater units must be installed throughout the city. The digipeaters operate at 5 watts. IES will provide support to City personnel who should do the installation of these devices. To communicate with a specific unit, a repeater path may be used to read it. Individual gateways can also be part of the path, so if there is a particular unit that can’t be directly reached by a digipeater, then a unit close to it may be used to repeat the message. All transmissions are digital packet.