Wimax Forum is an industry-led,
not-for-profit organization that certifies and promotes the compatibility and
interoperability of broadband wireless products of IEEE 802.16. Its goal is to
accelerate the adoption, deployment and expansion of WiMax technologies all
over the world, while facilitating roaming agreements, sharing best practices
within its members and certifying products [14].
WiMax forum has three
main areas of standardization development:
·
air interface specifications ,which
focus on the physical and the data link layer (layers 1 and 2 of the OSI
reference model) and are based on IEEE 802.16
·
network specifications, which apply to
higher layers and are not based on 802.16, but developed by WiMax Forum
·
roaming specifications, which deal with
the roaming business framework with functions for wholesale rating etc
The relationship
between IEEE 802.16 and the WiMax Forum with respect to the OSI reference model
is shown in Figure 12 [7].
The discussions in the
WiMax Forum is carried out by industrial delegates. It releases the Wimax
Forum’s Mobile WiMax System Profile, which does not describe precise
specifications (unlike the IEEE WirelessMAN standard), but only lists
functionalities and parameters that are to be used. This list enhances common
functionalities and interoperability among WiMax products. The relationship
between the WiMax standardization of these two entities is illustrated in
Figure 13. A very representative example of the standardization differences of
them lies in the physical layer, where IEEE 802.16 defines three options
(Single Carrier, Orthogonal Frequency Division Multiplexing and Orthogonal
Frequency Division Multiple Access), while the WiMax Forum refers only to
OFDMA, as it provides suitable operation only for mobile users [1].
Due to the potential
for very high growth and utilization, the WiMax Forum focuses its efforts on
Multichannel Multipoint Distribution Service, the 3.5 GHz licensed bands and
the unlicensed 5 GHz band.
The 9 Working Groups of
the WiMax Forum and their main functions are as follows:
·
the Network WG, that develops network
architecture specification, network procedures and protocols. It includes the
Network Interoperability Testing TG, which defines network-level
interoperability testing specifications.
·
the Technical WG, which develops technical
conformance specifications, system profiles and certification test suites for
the air interface.
·
the Application WG, that benchmarks,
characterizes and demonstrates best-practice solutions among different classes
of applications.
·
the Service Provider WG, which develops
the requirements on air-interface and network systems.
·
the Marketing WG, that promotes global
adoption of the WiMax broadband wireless technology and informs about the
progress and development of WiMax
·
the
Certification WG, which manages the WiMax Forum certification program with the
supervision of the test labs, the evaluation of the general tests themselves
and especially the network-related interoperability tests.
·
the Regulatory WG, that is in charge of
the spectrum policy and regulatory issues worldwide, promoting access to a
spectrum “fit for purpose” .
·
the Global Roaming WG, which is
responsible for the frameworks needed to achieve global roaming across the
various WiMax networks with the respective roaming guidelines, interfaces and
tests.
·
The Technical Steering Committee (or
Technical Plenary), that is promoting better cross-working-group coordination
and decision making on crucial issues.
The WiMax Forum issues
profiles, releases and certificates, each of the three with a different role.
The profiles are based on the IEEE 802.16 and ETSI HiperMAN standards [3].
Features that are optional in standards can be compulsory in a profile. At the
beginning, the WiMax Forum was focusing on the spectrum of 10-66 GHz, but later
on smaller frequencies were included. There are currently two system profiles:
the fixed WiMax system profile for systems based on IEEE 802.16-2004, with 256
carriers in OFDM and the mobile WiMax profile for systems of IEEE 802.16e-2005
amendment. The certification profiles are derived by the system profile and
depend on the spectrum used (eg 2.5 GHz or 3.5 GHz), the channel size (eg 1.25
MHz or 10 MHz etc) and the duplexing mode (frequency or time division duplex).
These three parameters are dependent on the local regulatory rules. Complying to
the same certification profiles ensures interoperability among products of
different vendors [7].
WiMax
Forum develops releases and waves within these releases, in order to implement
new features .The equipment that meets the standards of a release has to be
compatible with older releases. The release development process consists of six
stages. The requirements of the first stage are created by the Service Provider
WG, of the second to the fifth stage by the Technical WG, the Network WG and
the Global Roaming WG concerning the air interface, network and roaming
specifications. The major releases are 1, 1.5, 1.6 and 2, which are shown on
Table 2 [3] .
WiMax
Forum issues certificates for vendors, after they have submitted their products
for testing at the six WiMax Forum designated certification labs around the
world, which are in Spain, Taiwan, China, the USA, Malaysia and South Korea.
The testing itself takes place in these labs without the WiMax Forum involving
directly [7]. The certification process is described with the flow chart of Figure
14. After the equipment is submitted by the vendor, conformance and
interoperability tests are conducted, before the certification can be issued.
If any of the two tests fails, the process halts and the vendor is asked to
make the necessary changes in order to comply with the requirements.
When the certification
is finally issued, the product is added to the WiMax Forum Certified Product
Registry [7].
.jpg)
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου