The purpose of this standard is to define the air interface for radio tags optimized for use in visibility networks, where presence, identity and associated data can be determined from stationary or moving tagged items, in situ, within relatively arbitrary storage areas. 'In situ' in this context means that it is not necessary to either move the tagged items into closer proximity of a reader nor to move a reader into closer proximity of tagged items in order to identify the presence of a tag or to read or modify tag information. In addition to visibility networks, applications for the radio tags described in this document include sensors, effectors, battery operated displays and zero configuration peer to peer networks. This standard will facilitate compatibility and encourage inter-operability of routers, readers, base stations and radio tags from multiple manufacturers. It is expected that additional standards under the IEEE 1902 identifier will provide other physical link options, command sets and standardization of commands and operations for specific vertical market applications. This standard specifies operation in the 47CFR15.209 emission regulation environment where field strength levels are below the threshold of regulation and thus permits operation world wide without requiring action on the part of regulatory bodies or the acquisition of special site licenses. This standard specifies: - The functions and services required by an IEEE 1902.1 compliant device to operate within ad hoc networks. - The MAC procedures to support the delivery of MAC service data units (MSDU). - PHY signaling techniques and interface functions. - Operation of IEEE 1902.1 compliant devices within a wireless network that may co-exist with multiple other overlapping IEEE 1902.1 networks.