Digital Signal Processing Reference
In-Depth Information
Chapter 2
Emerging Standards for Smart Radios:
Enabling Tomorrow's Operation
2.1 Standards in Evolution
In this chapter we detail the standardization roadmap towards an increase in hard-
ware and policy flexibility, described in Chap. 1. This is shown in Fig.
2.1
.
First, we discuss the increase in hardware flexibility. While standards typically
do not discuss implementation-related aspects, we describe how parameters have
become more and more dynamic. This trend is clearly driven by the innovation in
the SDR, which is a reconfigurable platform solution that supports a range of air
interfaces. Without flexible implementation methodologies, this level of flexibility
could not have been introduced by standardization bodies. As shown in Table
2.1
,
we discuss standards for both cellular and distributed technologies.
Afterwards, we discuss the increase in policy or spectrum access flexibility. As
shown in Chap. 1, the ISM bands, where unlicensed devices coexist using only high-
level spectrum etiquettes, have been a clear driver towards more dynamic spectrum
access. In this chapter, we discuss two ways to counter the QoS problem with dy-
namic spectrum access. First, we discuss how the spectrum access is taken a step
back, by introducing more control mechanisms between the different standards in
the ISM bands. Specifically, we discuss the IEEE 802.11h standard, where algo-
rithms are developed to avoid interference from unlicensed ISM bands towards
satellite and radar systems and the IEEE 802.19 standard, which takes care of cross-
technology coexistence. The second way to counter the QoS problem of dynamic
spectrum access is to introduce a more hierarchical scheme, known as opportunis-
tic spectrum access. In opportunistic spectrum access, unlicensed devices can use
licensed spectrum as long as they do not interfere with licensed users.
In Chap. 1, we have discussed the CR as an intelligent control layer to han-
dle the increasing flexibility, introduced by SDR and OSA. In this chapter, we
show two standardization efforts that are in line with this view. We first present
the IEEE 802.21 Media-Independent Handover, which dictates how the a recon-
figurable radio can decide to switch between different standards. Afterwards we
discuss the IEEE DYSPAN Standards Committee (formerly SCC41), where tech-
niques are standardized in line with the CR paradigm to allow for a more advanced
adaptation and monitoring for Cognitive Radios.
