Requirement for AMPS System
The data modem used in the current analog system must
meet the following requirements.
1. Data transmissions have to use 30-kHz voice channels.
2. The SAT tone must be maintained at around 6000 Hz in
voice channels. Then the tr
INTELLIGENT CELL CONCEPT
What is the Intelligent Cell?
In the cellular industry, system capacity is a great issue.
As demand for cellular service
grows, system operators try to find ways to increase system
capacity. Capacity can be
increased by reducing t
COMPARING WiMAX AND 3G (HSDPA) FOR
MOBILE BROADBAND WIRELESS
The two systems are based on two different technologies
WiMAX is based on OFDM,40
and HSDPA is based on CDMA.41 The spectrum efficiency
comparison based on the two
different technologies is show
Digital Data Services
Usually, digital data services support two data service
groups: short message services and
bearer services.We describe the GSM short message
services and GPRS bearer services in
A. Short message service (SMS)
The GSM sh
The Philosophy of Implementing PowerDelivery Intelligent Cells
Many different wireless versions of an intelligent cell can
be used as long as they can deliver
power to the location of the mobile unit. The easiest
explanation is the analogy of a person
Power-Delivery Intelligent Cells
In general, there are three kinds of zone-divided cell
Sectorial Cells. Sectorial cells are used to reduce
interference. Usually sectorial cells
are used when the terrain contour in the cells i
Convertors. There are three pairs of converters in the
three-zone microcell system.
Each pair is used to connect the signals from the base site
to the designated zone site. The
converter (Fig. 16.12b) is a broadband device that can
Description of the Intelligent Microcell
An intelligent microcell system1718 was described in Sec.
16.13. This system can be applied
to analog and digital systems. To show the improvement
over AMPS provided by intelligent
microcells, the voice q
A frequency-hopping system can be used as a CDMA
system (FH-CDMA). The hopping pattern can be formed
as a code sequence. Frequency
hopping has been used in the past to overcome enemy
jammers in military applications.
There are two kinds
Processing-Gain Intelligent Cells (K 1
Philosophy of Implementing Processing-Gain Intelligent
Cells. The concept
of the processing-gain intelligent cell can be explained by
the analogy of many simultaneous
conversations in a big hall (Fig. 16.8).