Radio Frequency (RF) Based AMR Systems

A number of factors must be considered when evaluating an RF based AMR system. These include:

  •     Licensed or unlicensed frequency spectrum
  •     One-way or two-way communications
  •     Mobile or fixed network systems

Licensed or Unlicensed

In the United States, the Federal Communications Commission (FCC) regulates and manages the use of radio frequencies. They have allocated various frequency bands for specific purposes and use. In addition to the allocations, the FCC mandates how much power or signal strength can be used to communicate over these bands in any device.

The FCC grants specific licenses to users to operate within certain bands. These licensed users have the rights to use this spectrum, provided that they adhere to guidelines set forth for the devices' use. This includes the maximum power used and how close the device can operate next to an adjacent frequency user's device.

Other bands, although governed by the FCC, permit users to operate in certain frequencies without the need to secure a license. These unlicensed users are generally limited to very low signal power levels.

Regardless of the licensed or unlicensed nature of the frequency, all users are governed and monitored by the FCC.

Typical AMR systems may be either licensed or unlicensed. Generally speaking licensed systems operate over longer distances, but require the user to secure and pay for a license every year. Typical unlicensed systems in the United States operate in the Industrial Scientific, Medical (ISM) bands, with 902-928 MHz being the most popular. Many systems communicate using a modulation technique known as a spread spectrum that allows multiple users to occupy the same channels without interference.

Communication Type

One-way

One-way systems, as its name implies communicate normally in one direction only. Typical AMR systems that use one-way have the remote metered device transmit information from the meter location to a central receiver. In some cases, one-way systems might have a "wake-up" that alerts the remote devices to turn on and begin transmitting, in other cases, the end units transmit all the time.

The cost of a one-way transmission system is normally lower than that of a full two-way system. One-way systems are ideal for applications that require only basic information to be communicated. The frequency of how often a one-way system can be read is dependent on the receiving system. Some fixed network one-way systems can deliver information from remote devices every 15 minutes.

Two-way

Two-way systems, as the name implies, permits the communication of information from the remote meter location to the receiver, as well as, from the receiver to the remote meter location. These systems offer utilities more functionality, including on-demand meter reading, retariffing of the meter remotely, recharging of a pre-payment metering, immediate power failure alerts, remote connect and disconnect services, and other advanced services.

System Type

Mobile Pedestrian System

In a pedestrian system, meter readers walk down a street collecting the meter reading from the meter interface unit (MIU) via a radio frequency (RF) hand-held receiver. Once in proximity of a remote meter device, the unit captures the data and stores it in the hand-held device. Pedestrian systems are typically less expensive to deploy than vehicle or fixed network systems and are particularly well suited for either small utilities or utilities that want to implement a limited AMR installation, only targeting difficult-to-read meters initially. This system is usually upgradeable to a vehicle system. At the end of the shift the operator downloads the route information into a route management or billing system back at the utility office.

Mobile Vehicle System

In a vehicle system, a specially equipped van has the central receiver inside the vehicle. The meter reader collects the readings, simply by driving the vehicle at normal road speeds (25-35 mph) around the intended route. Once the driver is in radio range of the MIU, the unit can receive and process the meter reading data very quickly. Unlike other drive-by systems, the Blue Tower system does not require the operator to "interrogate" the MIU, providing a much faster and safer drive-by system. Once the meter reading information is collected by the receiver, data is then sent to the laptop computer where it is matched up with the pre-loaded route information. At the end of the shift the operator downloads the route information into a route management or billing system back at the utility office.

Fixed Networks

Another way of capturing data from remote locations is to permanently mount a radio tower and equipment in a central location. The tower is then connected to a central processing unit that captures the data from the field. Fixed networks are more suitable for a densely populated area or a multi-unit site to become a cost effective means of collecting meter readings. One of the advantages of a fixed radio network is the ability to capture readings on demand or on a more frequent basis. All fixed network systems are not two-way. In fact, most AMR systems today utilize one-way receivers for data collection from the meter location.

If you would like information on Blue Tower's fixed network system, please complete the info request form.

Copyright © BluTower Inc. - All Rights Reserved 2012 - This e-mail address is being protected from spambots. You need JavaScript enabled to view it. - www.blutower.com
Home - News - Products - Solutions - Case Studies - Distributors - Support - Contact Us