In GSM networks with wide coverage, the
improvement of uplink and downlink transmit power is of great importance.
The PBT is a power boost technology. In
PBT mode, the two TRXs in the double-transceiverunit are used as one TRX. After
modulation and DA conversion, one signal output is divided into two RF signals.
These two signals are amplified and then combined to form one signal. As the
two signals are aligned in phase, the transmit power is amplified and the
downlink signalstrength is increased.
In dynamic PBT mode, the timeslots
corresponding to the two TRXs of a double-transceiver unit are set to PBT mode,
and other timeslots are set to non-PBT mode. After the timeslots in PBT mode
are released, they can be set to non-PBT mode. Dynamic PBT makes full use of
idle timeslots and improves the signal strength in areas with weak coverage,
such as at cell edges,indoors, or in cars. Based on actual network conditions,
adjustments can be made to maintain the balance between capacity and coverage.
Dynamic PBT is mainly applicable to
concentric cells. In a concentric cell, when the downlink coverage in the
overlaid subcell is restricted, continuous coverage is impossible. In this
case, the TRX utilization is low if PBT is adopted.
Dynamic PBT
Dynamic PBT is timeslot-based.
Normally, two TRXs in a double-transceiver unit work independently. If
required, the two channels of the same timeslot number on the two TRXs work as
a channel group. That is, the two channels can be converted into a channel
group, and the channel group into two independent channels. This balances cost,
capacity, and coverage. Dynamic PBT increases resource utilization and assists
in expanding the coverage.