Zone based radio frequency identification

A method for determining whether a first identification device is located within a zone, the method comprising:

• operating a portable locator within the zone to determine a respective reliability of communication between the locator and a plurality of identification devices, the plurality comprising the first identification device and at least one second identification device, wherein:
• a. the first identification device is located within a periphery of a first communication pattern;
• b. each second identification device is located beyond the periphery of the first communication pattern and within the periphery of a second communication pattern;
• c. the first and the second communication pattern each respectively has a periphery such that communication with a provided identification device that is physically located beyond the periphery is less reliable than communication with a provided identification device that is physically located within the periphery;
• and
• d. the first communication pattern has a periphery substantially within the zone;
• comparing reliability of communication with the second identification device via the first communication pattern and reliability of communication with the second identification device via the second communication pattern to provide a result of comparison;
• and
• indicating, in response to the result of comparison, that operation via the first communication pattern is within the zone.

A locator comprising:

• a. a receiver that provides a signal having indicia of identification device presence within a communication pattern;
• and
• b. a processor that performs a method for determining whether operation of a portable locator is within a zone, the method comprising:
• comparing reliability of communication with an identification device via a first communication pattern and reliability of communication with the identification device via a second communication pattern to provide a result of comparison;
• and
• indicating, in response to the result of comparison, that operation via the first pattern is within the zone, wherein:
• (a) the first and the second communication pattern each respectively has a periphery such that communication with a provided identification device that is physically located beyond the periphery is less reliable than communication with a provided identification device that is physically located within the periphery;
• (b) the first communication pattern has a periphery substantially within the zone;
• and
• (c) the identification device is located beyond the periphery of the first pattern and within the periphery of the second pattern.

A method for determining whether operation of a portable locator is within a zone, the method comprising:

• comparing reliability of communication with an identification device via a first communication pattern and reliability of communication with the identification device via a second communication pattern to provide a result of comparison;
• and
• indicating, in response to the result of comparison, that operation via the first pattern is within the zone, wherein:
• (a) the first and the second communication pattern each respectively has a periphery such that communication with a provided identification device that is physically located beyond the periphery is less reliable than communication with a provided identification device that is physically located within the periphery;
• (b) the first communication pattern has a periphery substantially within the zone;
• and
• (c) the identification device is located beyond the periphery of the first pattern and within the periphery of the second pattern.

A method for preparing for zone-based communication, such communication using a portable locator, the method comprising for each zone:

• determining a respective set of locations comprising at least one location, each respective location for operating the locator within the zone, all points within the zone being on at least one respective line of sight from at least one location of the set of locations;
• and
• determining a respective set of communication pattern pairs comprising at least one pattern pair, wherein:
• (a) each pair respectively comprises a first pattern and a second pattern;
• (b) each respective pattern, operative with the locator, has a periphery such that communication with a provided identification device that is physically located beyond the periphery is less reliable than communication with a provided identification device that is physically located within the periphery;
• and
• (c) each respective first pattern has a periphery substantially within the zone;
• and
• (d) for each pattern pair, placing at least one identification device beyond the periphery of the first pattern and within the periphery of the second pattern.