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In his keynote presentation at the WiMAX Forum Global Congress event held in
Amsterdam last month, Barry West, who now heads up the international interests
of Clearwire, said one of his priorities in the coming months was to persuade
operators to adopt WiMAX Profile C.

At first glance, the need to do so might seem strange.  Why would any
operator not want to choose Profile C, which stipulates an open and
non-proprietary interface standard (R6) between the BTS and the ASN Gateway? 
As Profile C operators are not tied into one vendor for BTS and ASN Gateway
equipment, they can force prices down through playing off different suppliers
against each other.  They can also choose the suppliers that can best
support the functionality and services they want to offer over their network
rather than being tied to one vendor that might not be up to the job.

But, as West implies, the case for Profile C is not clear cut; if it were, he
would not need to campaign for its adoption.  Despite the apparent
advantages of Profile C, some ‘turnkey’ vendors are still successfully tempting
operators with the two other Profiles available between the BTS and ASN Gateway:
Profile A and Profile B.  As both Profiles can create vendor lock-ins, they
stand in the way of WiMAX interoperability progress between multiple vendors
and, potentially, lower equipment prices.

In some cases, though, there are strong arguments not to use Profile C,
particularly if operators can avoid the expense of a large ASN Gateway. 
While Cisco believes that Profile C is the better choice for WiMAX operators
offering mobility services, not least because it centralizes the decision-making
for call handoffs between different BTSs – which then makes it easier for the
operator to control RAN traffic and offer QoS – this functionality is clearly
not necessary for a WiMAX operator focused on fixed and portable services only. 
"Where handoff is not required, Profile B can be adequate," says Paul Sergeant,
Mobile WiMAX Solutions Manager at Cisco.  "Profile C still has some
advantages, even in this case – such as QoS – but it may not justify the extra
cost."

Profile B does not define any interface between the BTS and the ASN Gateway, so
it is possible for Profile B vendors to pursue proprietary solutions and lock in
their customers.  Due to increased customer demand, however, many of the
big WiMAX suppliers that started out by supplying profile B equipment, including
Cisco (through its acquisition of Navini Networks) are now shifting to Profile
C.  According to Sergeant, nearly all of Cisco’s 20-plus commercially
deployed WiMAX operator customers are moving from Profile B to Profile C. 
This is an encouraging sign for Barry West and all those in the WiMAX community
campaigning for open network architectures, particularly if R6 interfaces can be
fairly easily software-installed on Profile B kit as Sergeant indicates.

Profile C Stumbling Blocks

One potential fly in the WiMAX interoperability ointment is Motorola, which has
long been a Profile B supporter.  Although Motorola’s WiMAX literature
points out that its wi4 equipment is ‘functionally aligned with Profile C’ – no
doubt largely due to intense pressure from Clearwire to which it supplies
802.16e kit – there is a feeling in the WiMAX community that Motorola will not
be able to make the transition from Profile B to Profile C as easily as others. 
One senior executive of an independent ASN Gateway supplier, who wished to
remain anonymous, told Wimax.com: "Some companies have hardware pieces which are
very difficult to change to Profile C and Motorola is one of those companies. 
They may have a hard time making the change [to Profile C]."

One person willing to go on record about Motorola is Peter Ziegelwanger, CTO at
Wimax Telecom, a small operator with a network presence in Austria, Slovakia and
Croatia.  "[Profile C] is a complete change in Motorola’s core network
architecture and has a lot of impact on its existing networks," he says. 
Wimax.com was not able to get a response from Motorola regarding how many of its
customers it has moved from Profile B to Profile C, or to get an update on how
many interoperability partners it has (or is in interoperability testing) for
its BTS and ASN Gateway equipment.  However, with at least 19 WiMAX
contracts to its name, as well as what it says is more than 75 WiMAX
‘engagements’ in 44 countries worldwide, Motorola is a major WiMAX player. 
The speed that Motorola moves to Profile C will play a big part in how far the
R6 interface is made available in different parts of the world. 

Another big Profile C stumbling block is Alcatel-Lucent, which is a keen
advocate of Profile A and has no plans to develop Profile C WiMAX equipment. 
While the R6 interface is used between the BTS and the ASN Gateway under Profile
A, the RRM (Radio Resource Management) is split between the BTS and the ASN
Gateway: the RRA (Radio Resource Agent) resides in the BTS while the RRC (Radio
Resource Controller) is placed in the ASN Gateway.  The upshot is that
operators using Profile A must have the same supplier for the BTS and the ASN
Gateway.  And for some operators, if the price and performance is right,
Profile A is a reasonable (if not ideal) solution.  Wimax Telecom, for
example, selected Profile A equipment from Alcatel-Lucent to roll an 802.16e
network in Croatia. 

"We do not support an open R6 interface as there has been no market request for
it so far, at least in the ‘enhanced wireless DSL’ market segment that we are
targeting, and where we have seen the bulk of market activity in terms of WiMAX
deployments," an Alcatel-Lucent spokesperson told Wimax.com. 
"Additionally, the vast majority of WiMAX deployments are single RAN supplier
deployments, and even in those cases where there are networks supplied by
several RAN vendors they are typically split into different areas/cities, each
of them being supported by one RAN manufacturer."

Like Motorola, Alcatel-Lucent has a big 802.16e presence around the world. 
As of the beginning of 2Q 2009, the French-US supplier was supplying 802.16e kit
for 15 commercial networks worldwide, with a total of 36 Mobile WiMAX contracts
under its belt.  Alcatel-Lucent’s resistance to Profile C is and will be a
big restraining factor on the spread of R6.

Profile C Momentum

The Profile C question marks hanging over Motorola, plus the outright Profile C
defiance from Alcatel-Lucent, shouldn’t detract from the significant amount of
interoperability progress that has been made on IOT and partnership-forming
between different BTS and ASN Gateway vendors via the open R6 standard and
Profile C.  Much of the groundwork on this has been done – through
necessity – by the smaller standalone BTS vendors that don’t have the resources
to develop ASN Gateways, such as Alvarion, WiNetworks, Aperto and Airspan. 
They need Profile C to get a foothold into the market. 

The WiMAX Forum is also embarking on a NWIOT (Network Interoperability Testing)
certification program that will only rubber-stamp equipment using R6 as part of
Profile C.  The WiMAX Forum had previously taken the position of letting
the market decide between Profile B and Profile C – it had earlier dropped its
support of Profile A – much to the annoyance of the smaller, independent WiMAX
kit suppliers.

The WiMAX Forum’s unequivocal backing of Profile C is warmly welcomed by the
likes of WiChorus, a standalone supplier of ASN Gateways and Home Agents that
has been active in promoting Profile C through its own IOT initiative, the One
Open WiMAX program.  "We have reached the tipping point for Profile C,"
says Rehan Jalil, WiChorus’ CEO, "but still a lot of work needs to be done."
Part of that WiChorus work, says Jalil, is supporting base station vendors even
if they are not yet fully Profile C compliant.

In the past, turnkey WiMAX kit suppliers would typically say to their
prospective operator customers that Profile A or Profile B was the way to go
unless they wanted to get embroiled in time-consuming IOT with multiple vendors
with little chance of a satisfactory outcome.  That argument is much less
convincing now, particularly as Clearwire has been a staunch Profile C supporter
from the beginning.  Barry West, when persuading operators to go down the
Profile C route, can also say as part of his sales pitch that they don’t need to
do any IOT on vendors’ kit that has already been tested on Clearwire’s network.

Profile C looks the way to go for most operators going forward but it may take a
bit of time yet before it becomes what the open architecture proponents crave –
a de facto standard.

Ken Wieland has been reporting and commentating on the telecom industry for
15 years. He has held various senior editorial positions, including most
recently as Editor of WiMAX Vision magazine at Informa Telecoms & Media. Now
working as a freelance telecoms writer, Ken contributes analysis and opinion
pieces to a number of websites, including the EIU (Economist Intelligence Unit). 
He can be contacted at
ken2wieland@yahoo.co.uk.