Rationale for a Broadband Wireless Access Air Interface Standard:
Meeting the Five Criteria

1. Broad Market Potential

A standards project authorized by IEEE 802 shall have a broad market potential. Specifically, it shall have the potential for:

a) Broad sets of applicability

Access networks in the millimeter-wave region are a rapidly emerging technology on a worldwide basis. Such networks have the potential to compete with copper- and fiber-based systems in terms of capacity, and they offer the advantage of not requiring the installation of buried or pole-based infrastructure. This is particularly advantageous in countries where the infrastructure is not widely deployed. In the US, the recent auction of the LMDS frequency bands testifies to the level of interest in providing communication facilities based on broadband wireless. Similar allocation of frequencies in the millimeter region (above 10 GHz) is occurring in many other countries.

b) Multiple vendors and numerous users

The interest of many vendors is attested by the membership of the 802 Executive Committee Study Group on Broadband Wireless Access. Each of the 97 members, representing over 70 companies, participating in at least one of the Study Groups' two meetings (see Appendix A). NIST's N-WEST initiative, which aims for standardization in broadband wireless access, currently includes 58 supporting companies, 7 of which have enrolled since the January meeting. Two of the Supporting Companies are wireless trade associatons representing many more (see Appendix B).

Although broadband wireless access networks have only recently been deployed, many users are already on-line using proprietary systems. For example, one service provider in the US currently has facilities operating in over 40 cities.

c) Balanced costs (LAN versus attached stations)

Given that a base station in a point-to-multipoint network can serve many user stations, and a single user station can serve many users in the building, the cost of the equipment can easily be spread over many users. Typically it will represent a small fraction of the total investment in computing and telecommunications hardware.

2) Compatibility

IEEE 802 defines a family of standards. All Standards shall be in conformance with the IEEE 802.1 Architecture, Management and Interworking documents as follows: 802 Overview and Architecture, 802.1D, 802.1Q and parts of 802.1f. If any variances in conformance emerge, they shall be thoroughly disclosed and reviewed with 802.

Each standard in the IEEE 802 family of standards shall include a definition of managed objects which are compatible with systems management standards.

The proposed standard will conform to the 802 Functional Requirements Document, with the possible exception of the Hamming distance.

3. Distinct Identity

Each 802 standard shall have a distinct identity. To achieve this, each authorized project shall be:

a) Substantially different from other IEEE 802 standards.

The BWA standard occupies a distinct place in the family of standards. It is intended to provide for public access networks operated by a third party, where the user typically makes use of a wide-area network through an access network. It differs also from a wireless LAN, which typically is operated by a single organization over smaller distances and has less-stringent requirements for system integrity and resistance to unauthorized usage.

The access network is optimized for distances comparable with the propagation of millimeter waves through the atmosphere, which typically limits the distance between base stations and users to metropolitan dimensions.

b) One unique solution per problem (not two solutions to a problem).

It is envisioned that the standard will provide protocols sufficiently flexible to provide efficiently for a variety of services, some of which may have stringently bounded delay requirements. Hence it will not be necessary to have a multiplicity of different and incompatible versions.

c) Easy for the document reader to select the relevant specification.

It is anticipated that the document will be easily understandable for any reader attending the third and later IEEE 802 meetings, so long as one of those meetings is a plenary session.

4) Technical feasibility

For a project to be authorized, it shall be able to show its technical feasibility. At a minimum, the proposed project shall show:

a) Demonstrated system feasibility

The feasibility of such systems has been demonstrated by proprietary systems covering some if not all of the capabilities intended for this standard and now going into operation in many cities worldwide.

b) Proven technology, reasonable testing

The radio technology in millimeter-wave systems has been demonstrated for many years in both point-to-point and point-to-multipoint systems, as used in commercial and military environments. Many systems are now in commercial use.

c) Confidence in reliability

Commercial deployment of point-to-point and point-to-multipoint systems at millimeter-wave frequencies by carriers is evidence of proven reliability.

5) Economic feasibility

a) Known cost factors, reliable data

The economic feasibility of the equipment has already been demonstrated at the level of proprietary systems now going into operation. The willingness of investors to spend large sums to acquire spectrum rights, plus the large additional investment required for hardware in public networks, attests to the economic viability of the wireless access industry as a whole.

b) Reasonable cost for performance.

The use of such methods as point-to-multipoint communication provides substantial economies relative to earlier point-to-point technologies, particularly in handling data, which is characterized by high peak demands but bursty requirements overall. As demonstrated in many IEEE 802 standards over the years, such shared-media systems effectively serve users whose requirements vary over time, within the constraints of the total available rate. The cost of a single base station is amortized over a large number of users.

c) Consideration of installation costs.

Installation of any wireless customer-site system is relatively simple in that no offsite cabling need be installed. In contrast, with wireline networks the plant expense to connect the customer to the network is a very substantial part of the total cost and must be incurred for the first user in a coverage area. With wireless, the expenses can be incurred as customers come on-line. The siting of base stations is a more complex issue, but since one base station supports many users, the costs involved are very nominal on a per-user basis.

Appendix A:
The 802 Executive Committee Study Group on Broadband Wireless Access

The Study Group had 97 Members (from over 70 companies), each of whom attended either the January 13-15, 1999 meeting in Orlando, or the March 9-11, 1999 meeting in Austin. See the Membership List.

Appendix B:
N-WEST Supporting Companies (updated March 11, 1999)


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Roger Marks (r.b.marks@ieee.org)