User's Manual Chapter 13

Base FCC Regulatory Test Report
7-104
AT&T Wireless Services
FCC Type Acceptance Application
10991 Rev. 1.0 7/6/99
supports a means by which RUs can maintain constant frequency
synchronism with the base.
The Base RF signal contains 17 Remote Synchronization Pilots (RSPs),
which are used to provide frequency transfer across the airlink (refer to
Figure 7.16—). Of the 17 RSPs, the outside eight are transmitted
continuously by all base stations (simulcast) and nine are transmitted in
a time-keyed manner. The inner nine RSPs are time keyed to be
energized only during the CLC frames that correspond to the Base
Station Offset Code (BSOC). For example, if the BSOC is 02, the time-
keyed RSPs will be energized during the NAC frame containing
Figure 7.16—RSP Definitions
BC time slot 02 and its four subsequent CLC slots. The time-keyed
RSPs will remain inactive during the remaining 31 NAC frames. The
presence of the time-keyed RSPs are used to direct the receiving RU to
the correct broadcast frame boundary for the serving Base. Regardless
of whether an RSP is simulcast or time-keyed, each pilot is assigned a
fixed amplitude and phase component, the parameters of which are the
identical between all base stations and selected to minimize the overall
peak-average ratio of the transmitted bursts.
All Bases obtain their frequency reference from an internal clock which
is disciplined by a Global Positioning System (GPS) receiver. The use
of GPS assures a minimal frequency offset between base stations,
which is essential for minimizing co-channel beat-note interference.
The RU is also capable of generating a variant of the Bases’s RSP tones
known as Delay Compensation Pilots (DCPs). DCPs occupy the same
relative positions in the baseband signal as RSPs, however, they are
RSP 0 RSP 1 RSP 2 RSP 3 RSP 4 RSP 5 RSP 6 RSP 7 RSP 8 RSP 9 RSP 10 RSP 11 RSP 12 RSP 13 RSP 14 RSP 15 RSP 16
Simulcast Time-Keyed Simulcast Simulcast Simulcast Time-Keyed Time-Keyed Time-Keyed Time-Keyed Time-Keyed Time-Keyed Time-Keyed Time-Keyed Simulcast Simulcast Simulcast Simulcast