TIA-902.BAAB-A:2003 (R2013)

The scope of this document is to define the physical layer (PHY)
of the Scalable Adaptive Modulation (SAM) Wideband Air Interface
(WAI). The WAI called Uw is the interface between the fixed network
equipment (FNE) and a subscriber unit (SU) or directly between
subscriber units in a wideband system. The general wideband system
model is shown in Figure 1, and illustrates the Radio to FNE Mode
of operation.

The WAI physical layer is between the Base Radio (BR) of the
Fixed Station (FS) and Mobile Radio (MR) of the Subscriber Unit
(SU). Alternately, it may be between the MR of one SU and the MR of
a second SU, and is used for wireless communications between these
functional groups. This document and the Wideband Air Interface SAM
Radio Channel Coding (CHC) [1] document together make up the OSI
layer 1 of the SAM WAI. Figure 2 shows the relationships between
the OSI layers for the radio to FNE interface.

This document concentrates on the physical layer, whose function
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 the physical layer concentrates on the following subjects:

• Modulation

• Pulsed transmission turn-on and turn-off for inbound

• Mechanism for time division multiplexing (TDM)
synchronization

• Definition of TDMA frame structures

• Mechanism for amplitude and phase recovery

SAM 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 permits SAM to adapt its performance by delivering
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 SAM is time division multiple-access (TDMA). The outbound
transmission mode is continuous, while the inbound transmission
mode is pulsed on a slot-by-slot basis. The number of inbound slots
transmitted in by any given MR is not specified in this document.
An MR may transmit in any number of inbound slots, up to the total
number of inbound slots defined for the system depending upon
control information from higher layers.

Layer 1 reserves certain symbols within the information stream
to provide for its operation. These reserved symbols are used to
synchronize to the radio channel and to provide a known reference
for performing coherent demodulation of the subchannels. Many
special terms used in this document are defined in the terms
contained in Section 2.