Wireless Future - Telenor

As sampling at RF is not possible with the current
converter and signal processing technology,
the radio signal has to be converted to an intermediate
frequency. The programmable up- and
down converters perform the most intensive processing
tasks like filtering, modulation, and
demodulation.
Signal-to-Noise Ratio (SNR), Signal-to-Noise
and Distortion (SINAD) radio, Spurious Free
Dynamic Range and Total Harmonic Distortion
(THD), e.g. for multi-tone operation, are important
radio performance parameters. The converters
and signal processing part of the SW radio
have to comply with the specifications given in
the specific radio standard.
Table 1 provides an overview of SW radio critical
parameters, the status of technology as of
today and the expectations to be met for a SW
radio terminal implementation.
4.2 SW Implementation and
Download
The major challenge for the standardisation for
SW radio is the definition of methods for SW
download. This implies two aspects, the standardised
interface for all terminals and the
method for SW upgrade.
Manufacturers are likely to develop proprietary
products. Therefore SW radio has to find a way
to make the radio interface independent of the
hardware platform. Like in computer systems,
two potential solutions are seen:
• Develop a common HW platform and operating
system. Even though this would allow an
easy implementation of SW radio, the scenario
is quite unlikely. As of today, a couple
of operative systems are known for terminals
and PDAs, as e.g. EPOC, PalmOS and PocketPC.
It is not likely that manufacturers will
join on one single platform and operative system.
Telektronikk 1.2001
Parameter Current state Future goal
A/D, D/A converters Sampling rate, bandwidth, linearity, 14 bit, > 80 Msps 16-bit, 400 Msps
SNR, power dissipation BW > 25 MHz BW ~100 MHz
SFDR, SNR > 70 dB SFDR, SNR > 100 dB
Dynamic Up/Down Bandwidth, I/O rate, tuning resolution, 16 bit, > 60 Msps Multi-channel X x 5 MHz
Converter (DUC, DAC) multi-carrier/channel support BW 5 MHz
SFDR > 90 dB
SFDR > 100 dB
DSP Processing power, run time support, 16-bit, 2 billion MACs Higher performance,
power dissipation 32-bit, 500 million MACs efficient C-code execution
Power Amplifier (PA) Linearity, power dissipation BW > 60 MHz BW > 100 MHz
Gain up to 40 dB Gain up to 80 dB
• Resident compilers. The compiler generates
an executable code specific to the hardware
platform on which the code runs. This scenario
allows differentiation on the supply side.
Java could be a suitable candidate for a resident
compiler. Even though extensions for a real-time
operative system are needed, most platforms
have already today a virtual Java machine implemented.
Further advances will come with DSP
supporting Java directly [TI].
Figure 6 provides an overview of the hardware
and software in a SW radio context: the virtual
machine or virtual radio platform allows to
abstract SW from the manufacturer specific
hardware.
Most authors regard the reconfigurability of the
air interface as the most important feature of a
SW radio terminal. Reconfiguration of the service
functionality is of the same importance
[Daneshgaran2001]. Figure 7 provides an overview
of capabilities of a future SW radio termi-
Programmability
SW applications
API support engine
Reprogrammable
radio interface
Virtual machine
Hardware
Table 1 SW radio critical
parameters [P921D1]
Figure 6 Relationship between
HW and SW in an SW
radio context
User application
SW libraries
Signal processing modules
Real-time control modules
Hardware interface modules
Resident compiler
Real-time operating system
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