ABSTRACT
Software-defined radio system architecture must be openly structured to various system standards. It should also provide capability for distributed processing, object-oriented design, and software controllability. This implies that the software to be used in the SDR system should be independent of a given hardware platform. In order to achieve these goals, the proposed SDR system utilizes modularization to maximize hardware reuse and design flexibility, which provides the system reconfigurability. The objective of this article is to provide an open architecture of a smart antenna base station (SABS) operating in the SDR with architecture that is object-oriented and software-controlled. For this purpose, the software and hardware of a SABS is first modularized and partitioned into modules, respectively. Then the interface among the modules is specified to determine the smart antenna
application programming interface proper for the SDR network. The suitability of the proposed open architecture of SABS is verified through a design example of SABS implemented in accordance with the proposed architecture. The performance of the proposed system is shown in practical signal environments of CDMA2000 1X with commercial handsets operating at various data rates ranging from 9.6 to 153.6 kb/s in terms of frame error rate and signal- to-Interference-plus-noise ratio, which is dramatically improved through the nicely shaped beam pattern.
INTRODUCTION
The objective of developing software-defined
radio ( SDR) technology is to realize plural system
standards on a single hardware platform
that is implemented mainly with high-speed programmable
digital signal processing devices [1].
A desired system standard can be selected by
choosing a proper software module.
This article addresses the problem of designing
the hardware and software architecture of a smart
antenna base station (SABS) that operates in an
SDR network. A design example of SABS architecture
that satisfies the requirements of SDR
functionalities is also provided in this article. We
propose a hardware platform employing the open
architecture of SABS, with which one can implement
the multimode SDR system by selecting the
mo dularized software. Note that the hardware
platform itself remains unchanged while selecting
a desired system standard among several different
standards [2].
The SDR technology includes the design of
both hardware and software modules. The hardware
module is reconfigured by the software
module, which means that a given hardware
platform is converted into a specific system standard
or special-purpose communication system
depending on the changes in the software module. I
t is key to SDR technology that a system
update or an addition/deletion/modification of
services can be performed extremely easily without
changing the existing hardware [3].
In this article we present an open architecture
of SABS that is suitable to the SDR network
and allows one to fully exploit the merits of
both smart antenna and SDR technologies. The
proposed architecture has been applied to implement
a system of SABS, which includes the modulation
and demodulation parts of the SABS
together with the interfaces with the SDR network,
as well as that among the modules within
the SABS. The suitability of the proposed open
architecture is demonstrated through a quantitative
analysis obtained through various experimental
measurements provided from the design
example of SABS.
The main contributions of this article can be
summarized as follows. First, SABS has been partitioned
into small modules in accordance with
the function of each module. The interconnections
among modules are specified such that the
clock/control signals and command data buses
between all connected modules operate properly.
Second, a new SABS open architecture (SABS
OA) together with a smart antenna application
programming interface (SA API) are presented
such that the required features of the SDR system
are fully satisfied in the SABS. Third, the
SABS OA and SA API presented in this article
have been developed in such a way that the
vari
ous beamforming algorithms are applicable to the
roposed OA. This means that one can receive
any of the beamforming algorithms suitable to a
given signal environment from the SDR network
through the software download procedure. Finally,
utilizing the OA proposed in this article, we
present an example of SDR-based SABS to experimentally
show the feasibility of the proposed
SABS OA in a practical signal environment.
NAMKYU RYU, YUSUK YUN, AND SEUNGWON CHOI, HANYANG UNIVERSITY, SEOUL, KOREA
RAMESH CHEMBIL PALAT AND JEFFREY H. REED,
VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY
No comments:
Post a Comment