RE: stds-80220-requirements: Definition of "air interface"

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Geoff, et. al.

Let me try to be a bit clearer why I am suggesting we stick with air-interface and why I do not think the term radio-link is appropriate in this context.

First, I wholly endorse using terms that are well understood by the industry and defined by others - if we use them to refer to the same thing. That is actually why I believe that using radio-link and radio-link protocol for what 802.20 is doing is inappropriate. The term radio-link and radio-link protocol (RLP) in 3G have very specific meanings. In particular the RLP is actually a protocol above the MAC layer (see 3GPP2 C.S0024 and e.g. 3G document 24.022) - it certainly does not include the PHY and MAC layers. So if we were to refer to what we are specifying as part of the RLP we would actually be creating confusion with the 3G community rather then helping them understand.

On the other hand, the term air-interface is in common usage by organizations working on both fixed wireless and mobile specifications.

802.16's title refers to "Air Interface" and the first sentence in the base 802.16 standard reads " This standard specifies the air interface, including the medium access control layer (MAC) and physical layer (PHY), of fixed point-to-multipoint broadband wireless access (BWA) systems providing multiple services."
3GPP2 has specifications with titles such as "cdma2000 High Rate Packet Data Air Interface Specification" [3GPP2 specification 3GPP2 C.S0024]. Below is a diagram from that specification showing where the air-interface is:

[Figure from page 1-2 ]

That is clearly consistent with definition 2.

So on balance I believe the correct choice is to stick with the term air-interface; this will facilitate communications with other groups. The base standard, just like 802.16's base standard, can then add the appropriate qualifiers as to which layers and/or aspects of the air-interface are being addressed.

Regards

Mark Klerer

-----Original Message-----
From: Geoff Anderson [mailto:meerkats@hvc.rr.com]
Sent: Wednesday, October 08, 2003 7:16 PM
To: 'Klerer Mark'; 'Jim Mollenauer'
Cc: 'Gang Wu'; stds-80220-requirements@ieee.org
Subject: RE: stds-80220-requirements: Definition of "air interface"

Mark,

Thanks for the comments. I think your discussion actually made the case for getting rid of the term air-interface because it really does lack any descriptive information about what we are developing.

Therefore, I would use the language of your definitions with the following changes:

Definition:

1) The radio-link is the radio-frequency portion of the transmission path between the wireless terminal (usually portable or mobile) and the active base station or access point.

2) The radio-link is the shared boundary between a wireless terminal and the base station or access point.

The introduction to the final standard would read:

This standard specifies the layer 1 and layer 2 Radio Link Protocol or RLP, between compliant wireless terminals and base stations.

I don't think there is anything that would preclude us from using terminology that is already used in other standards. In fact, this may help many of our 3GPP/2 members understand what it is we are trying to standardize, since they have already done it.

Best Regards,

geoff

Geoffrey T. Anderson

Polar Industries, Inc.

45 Roe Avenue

Cornwall on Hudson, NY 12520-1403

Phone: 845-534-4589

Fax: 845-818-3513

Cell: 914-843-9572

-----Original Message-----
From: owner-stds-80220-requirements@majordomo.ieee.org [mailto:owner-stds-80220-requirements@majordomo.ieee.org] On Behalf Of Klerer Mark
Sent: Wednesday, October 08, 2003 4:23 PM
To: 'Jim Mollenauer'; Geoff Anderson
Cc: 'Gang Wu'; stds-80220-requirements@ieee.org
Subject: RE: stds-80220-requirements: Definition of "air interface"

I agree with Jim Mollenauer. Specifically the term RLP as used by Jim Tomcik actually refers to a very specific protocol used in UMTS. Here is the definition of RLP:

RLP - Radio Link Protocol

Radio Link Protocol terminates at the MS (Mobile Station) and the IWF (Interworking Function) generally located at the MSC (Mobile Switching Centre). It utilizes the reliability mechanisms of the underlying protocols in order to deliver data. (http://www.mpirical.com/companion/mpirical_companion.html#http://www.mpirical.com/companion/GSM/RLP_-_Radio_Link_Protocol.htm)

I would like to toss out the following for people to consider.

Considerata: The word "Interface" is somewhat ambiguous in that we are using it in the two senses given in Webster's:

2 a : the place at which independent and often unrelated systems meet and act on or communicate with each other <the man-machine interface> b : the means by which interaction or communication is achieved at an interface

we seem to be using it in both the sense of 2a and 2b. This is the root of the difference in the two definitions that have been shared. So we could speak about an air-interface and even an air-interface interface.

We have the definition provided by Gang Wu (via the Intel website) : the air interface is the radio-frequency portion of the circuit between the cellular phone set or wireless modem (usually portable or mobile) and the active base station.

And the one provided by Dan Gal (via the Ericsson web-site): "The air interface is the shared boundary between a mobile and the base station."

IEEE 100 (The Authoritative Dictionary of IEEE Standards Terms) provides the following "general definition" [def 4] for "interface": A shared boundary

Suggestion for a way forward:

I would therefore suggest the following: We define air-interface as:

Definition:

1) The air interface is the radio-frequency portion of the transmission path between the wireless terminal (usually portable or mobile) and the active base station or access point.

2) The air interface is the shared boundary between a wireless terminal and the base station or access point.

I am trying to avoid using air-interface interface, and I believe that 2 in essence is taking a look at the "cross section" of the air interface between the mobile and base station. I have paraphrased definition one to remove the term "circuit" and replace it with the more generic "transmission path" due to the potential connectionless packet nature of the path.

The intro/preamble to the actual standard could then read eg:

This standard specifies the layer 1 and layer 2 protocols of the air-interface between compliant wireless terminals and base stations. (English to be fixed and polished when we get there).

In the requirements document we can put a similar statement in the overview. Note that the discussion as to whether we indicate what layer a requirement applies to is a separate issue.

This is in line with IEEE standards, 3G standards and ISO standards that all use the term air interface in a similar manner.

Sorry about this somewhat lengthy epistle. I hope it helps in getting us towards closure.

Mark

-----Original Message-----
From: Jim Mollenauer [mailto:jmollenauer@technicalstrategy.com]
Sent: Wednesday, October 08, 2003 3:04 PM
To: Geoff Anderson
Cc: 'Gang Wu'; stds-80220-requirements@ieee.org
Subject: Re: stds-80220-requirements: Definition of "air interface"

I respectfully disagree. A protocol and an interface are not the same thing. A protocol specifies what happens when, and generally involves several information transfers across one or more interfaces. An interface is the boundary between two entities, across which information may flow according to some protocol.

The term "air interface" emphasizes that we are standardizing the information flow through the air between two systems, and not across some internal wired interface within one of the systems. Calling it a "radio link" is confusing: does that imply link layer or physical layer?

Let's keep "air interface".

Jim Mollenauer

Geoff Anderson wrote:

I think Jim Tomcik had discussed a term Radio Link Protocol, or RLP during the San Francisco meeting. After replacing Air Link with Radio Link or Radio Link Protocol in the document and then re-reading, it seems to make much more sense.

I would agree with Alan's 10/2 proposal to remove Air Interface and replace with Radio Link or Radio Link Protocol where it makes sense. Also this decision would carry forward to all documents of 802.20, as Alan proposed.

geoff

Geoffrey T. Anderson

45 Roe Avenue

Cornwall on Hudson, NY 12520-1403

Phone: 845-534-4589

Fax: 845-818-3513

Cell: 914-843-9572

-----Original Message-----
From: owner-stds-80220-requirements@majordomo.ieee.org [mailto:owner-stds-80220-requirements@majordomo.ieee.org] On Behalf Of Gang Wu
Sent: Thursday, October 02, 2003 2:33 PM
To: stds-80220-requirements@ieee.org
Subject: stds-80220-requirements: Definition of "air interface"

At least I found one from the web.

"In cellular telephone communications, the air interface is the radio-frequency portion of the circuit between the cellular phone set or wireless modem (usually portable or mobile) and the active base station."

from http://searchmobilecomputing.techtarget.com/gDefinition/0,294236,sid40_gci339211,00.html

Regards,

Gang Wu