scope:

The scope of this document is to define the physical layer, or layer 1, of the IOTA/OFDM Modulation (IOTA) wideband air interface. The wideband air interface called Uw is the interface between the fixed network equipment (FNE) and the subscriber units or directly between subscriber units in a wideband system. The function of layer 1 is to convey information through the radio frequency channel, while contending with various channel impairments such as noise, interference, radio multipath, and delay distortion. The definition of layer 1 concentrates on the following subjects:

• Modulation

• Pulsed transmission turn-on and turn-off

• Mechanism for time division multiplexing (TDM) synchronization

• Definition of TDMA frame structure

• Mechanism for amplitude and phase recovery

• Radio channel coding

IOTA has been designed to deliver a flexible bit rate in 50, 100, and 150 kHz radio channel bandwidths in the 700 MHz band. This flexibility allows IOTA to optimize performance by allowing higher system data throughput under good signal conditions while still supplying significantly better throughput than current systems under weaker signal conditions. The basic mode of operation for IOTA is time division multiple-access (TDMA). Layer 1 reserves certain symbols within the information stream to provide for its operation. Many special terms used in this document are defined in Section 2.