Cell phone technical question

Status
Not open for further replies.

Rred

Member
Joined
Nov 21, 2014
Messages
830
Upman, you may be correct about TDMA being a method not a protocol. However, since the Academie Francaise has no issued a formal opinion on this, and multiple respectable sources including the University of Rochester, Ubiquiti Networks, and others, all expressly say that FDMA, CDMA, and TDMA are protocols...

I think you'd have to find the patent applications and see how they define it, to win that battle. And if the term has been misappropriated and changed in common use? You'll win the batle but still not win the war.

Unlike TCP/IP, which is a protocol twice by virtue of its own name, TDMA offers no clue.
 

UPMan

In Memoriam
Premium Subscriber
Joined
Apr 19, 2004
Messages
13,296
Location
Arlington, TX
Time Division Multiple Access (TDMA) simply means that the data stream on a frequency is divided into multiple time slots, each time slot containing data for one particular user or "channel" at any particular point in time. TDMA does not define the method of encoding the data itself, the bandwidth used, the frequency used, etc. It is a very high-level nearly generic term for a particular method of sharing multiple channels on a single frequency.

DMR and APCO Project 25 Phase 2 are two examples of specific protocols that utilize TDMA methods (specifically, they use two-slot TDMA so that two channels can be simultaneously used on the same frequency). The data itself is encoded using variations of the DVSI patented voice codec.

Simply asking "Can a scanner decode TDMA?" isn't a meaningful question, as TDMA is not a specific protocol.
 

mikewazowski

Forums Manager/Global DB Admin
Staff member
Forums Manager
Joined
Jun 26, 2001
Messages
13,641
Location
Oot and Aboot
Time Division Multiple Access (TDMA) simply means that the data stream on a frequency is divided into multiple time slots, each time slot containing data for one particular user or "channel" at any particular point in time.

Well said. All TDMA describes is the process of dividing a signal up into timeslots.

The protocol is what determines how the data is divided up into those timeslots.
 

slicerwizard

Member
Joined
Sep 19, 2002
Messages
7,662
Location
Toronto, Ontario
Upman, you may be correct about TDMA being a method not a protocol. Unlike TCP/IP, which is a protocol twice by virtue of its own name, TDMA offers no clue.
Of course he's correct. You're suggesting that something as simple as using a pen and paper is a protocol, when it's what you commit to the paper with that pen that is the protocol. If TDMA is a protocol, then so is plain old vanilla analog FM. Y'know, that analog FM method we all know and love...
 

Rred

Member
Joined
Nov 21, 2014
Messages
830
Slicer, I'm not suggesting any such thing. And I said that he may indeed by technically correct.

BUT. Several major players in the industry, hardware and software sides, all seem to think it is a protocol. Not anonymous people on the internet (who could be CEOs and patent holding PhD EE's for all I know) but major corporate players, who make their millions dealing with TDMA.

Now if you really want to get confused, ask the experts why the ITU allows "4G" in the US to be totally out of conformance with global standards. Or why "LTE" is totally different from both forms of "4G", even though it is called "4G LTE". Then ask them why LTE is neither CDMA nor TDMA, but utilizes aspects of both so it can be--and is--also considered to be BOTH.

Like arguing with a broadband provider that a "modem" is neither a bridge nor a router nor any one of a dozen other terms. The fact remains that without an "Acadamie Anglais" to regulate these terms, or a citation in the CFR, the terms will come to mean whatever they are used to mean. And having a green light won't matter to the bus that turns you into paste in an intersection while it is running a red one.

As I said, maybe he is right. You'd have to look at the patent application for TDMA to see if the INVENTORS of it refer to it as a protocol. Perhaps correctly, perhaps not. The USPO has been known to make mistakes as well. Like issuing a patent for the wheelbarrow, and several perpetual motion machines.
 

RRR

OFFLINE
Premium Subscriber
Joined
Dec 6, 2005
Messages
1,991
Location
USA
Don't you love it when "Wikipedia" is blindly considered a reliable source of information?
 

Rred

Member
Joined
Nov 21, 2014
Messages
830
And who cited the Wikipedia, besides yourself?
The Wiki folks are the first ones who'll tell you, confirm with original sources. They're short of fact checkers and editors, who are all unpaid volunteers.

"Method of timestamp synchronization of a reservation-based TDMA protocol
US 6347084 B1" Granted by the US Patent Office to the U.S. Philips Corporation in response to a 1998 filing.

Try finding an earlier filing, but Philips seems to think the Time Domain Multiple Access protocol is...a protocol?
 
Last edited:

UPMan

In Memoriam
Premium Subscriber
Joined
Apr 19, 2004
Messages
13,296
Location
Arlington, TX
That patent is in regards to a protocol (for synchronizing time stamps) which utilizes TDMA. The word "protocol" is being incorrectly interpreted as only modifying "TDMA" when it actually modifies that entire phrase. The sentence is actually written poorly, which is not unusual to find in USPTO titles (they are many times intentionally dense, convoluted, and obtuse).

As to citing a journal rather than Wikipedia, try: Fundamentals of Communications Access Technologies: FDMA, TDMA, CDMA, OFDMA, AND SDMA | Communications content from Electronic Design

Generally, a communications protocol defines all parameters required in order to establish and maintain a link between two or more radio devices. Just saying "TDMA" does not provide the necessary information to do so. It is one part of the protocol, but the protocol itself is made up of many additional parts. "My protocol uses TDMA" is a perfectly valid sentence, as it is clear that TDMA is a part of the protocol, not the whole. "I use TDMA protocol" is not valid, as it implies that TDMA in and of itself defines all the parameters needed.
 
Status
Not open for further replies.
Top