Good Evening everyone:
On October 21, 2000, I sent the following three questions to Mr. Nico van Waes of Nokia, Chair OFDM Forum FWA-WG. His reply with permission is below in its entirety and unchanged.
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Good Evening Mr. van Waes:
I would like to ask three questions.
1. Why did Nokia join the OFDM Forum and not VOFDM or COFDM?
2. What advantage does OFDM have over VOFDM and COFDM?
3. Do you feel that OFDM will be a Global standard?
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Mr.. Wong,
Since I do not know the reason for your inquiry, I must inform you of the following. It is Nokia policy that all official communications be done through our corporate communications office. I can hence answer question two and three on behalf of the OFDM Forum and only give you my personal opinion and some facts on the first. None of it should be construed as official Nokia statements and may not be presented as such.
If you would like to have Nokia's official statement , you will have to contact our corporate communications office:
Nokia Corporate Communications, Americas
6000 Connection Drive
IRVING, TX 75039
USA
Tel. +1 972 894 4573
Fax +1 972 894 4706
Email:
communication.corp@nokia.com
Ad 1: VOFDM and COFDM are forms of OFDM. VOFDM is a Cisco technology. The BWI Forum, which is entirely dictated by Cisco and Broadcom, has the sole aim of promoting VOFDM. VOFDM means Vector OFDM, and is based on using OFDM with multiple transmit and receive chains. Transmit and receive chains are by far the most expensive elements of a wireless device, which makes VOFDM a more expensive solution than single transmit/receive implementations.
As Nokia Wireless Routers, the business unit which I represent, focuses predominantly on the Fixed Wireless Access residential (i.e. single family and home office) market segment, cost is a crucial factor. Therefore, both the nature of the BWI Forum, the origin of the technology, as well as the technology cost would make it difficult for our business unit to support.
As a side note, the BWI Forum was established purely in response to the OFDM Forum, since Cisco and Broadcom, who were invited to the OFDM Forum's kick-off meeting, apparently felt the risk of not being able to convince the Forum of the superiority of VOFDM over other forms of OFDM too high.
COFDM, Coded OFDM, is a technology originating from DVB standards. DVB and FWA have different market segments as target. DVB focuses on video broadcasting, FWA focuses on "Internet" services. Hence joining a DVB Forum would be an odd choice for a FWA oriented business. In an OFDM based FWA standard, coding will be required, both for robustness and privacy, so in a sense it will be Coded OFDM as well. Whether it will be the same coding as in the DVB standards remains to be seen. There are other major drawbacks to the DVB standards when one tries to apply them to FWA, but those are mainly MAC/DLC issues.
The OFDM Forum is open to all forms of OFDM, and hence for Nokia's purposes the best fit, since there is room left to influence and optimize the implementation of OFDM best fitted for our FWA solutions.
Ad 2: Again, there are many implementations of OFDM, VOFDM and COFDM being among them. The OFDM Forum FWA- working group has as goal to drive towards one unique implementation of OFDM for all OFDM-based FWA standards. Although the member companies certainly have an interest in promoting their own implementations, the Forum is open to all implementations (we for example also invited the VOFDM proponents to give a speech at our meetings). The Forum will promote these implementations in IEEE, ETSI etc.., and work to get all FWA-standardizing bodies to accept the same standard, irrespective of what specific implementation it ends up being. The final choice is obviously dictated by the standardization bodies themselves, not by the OFDM Forum. The OFDM Forum FWA working group is not planning on releasing its own specific implementation as standard, like the BWI Forum does, unless the standardization bodies decide on a standard based on a single carrier technology.
Ad 3) The OFDM Forum is confident that the various FWA standardization groups (ETSI BRAN 'FWA < 11 GHz', IEEE 802.16.3, IEEE 802.16.WirelessHUMAN etc..) will select OFDM. That is not the issue. The issue is to make them all select versions of OFDM that are sufficiently similar to be implemented in one chip (in analogy to the IEEE 802.11a and ETSI BRAN HiPerLAN/2 OFDM based Physical layers) . On top of this, we will need to work to get the same spectrum allocated worldwide for these standards. So clearly, we have sufficient challenges left for the OFDM Forum to put its teeth in.
Sincerely,
Nico van Waes, Ph.D.
Chair OFDM Forum FWA-WG
ofdm-forum.com
Nokia Wireless Routers
nwr.nokia.com |
