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Have you been good boys and girls this year? If so, come sit on my knee and I’ll see if I can find a new standard for you in my bag. My, it is so full and heavy this year!
Well, okay, perhaps people would prefer a sleek new wireless phone under the tree this year, but many of the sexy new features of phones are due to new generations of cellular and PCS standards produced by the TIA (Telecommunications Industry Association). Consumers are becoming used to calling number identification, and short message service that are increasingly provided with digital phone packages (and even some analog). But, the marketing and engineering folks are not done yet! In such a competitive industry, there is no such thing as too many features. Competition is not just between carriers, but between the PCS and cellular industry segments, and between digital technologies: CDMA and TDMA (and with pressure from the capabilities provided by GSM). There are even occasional bursts of innovation from analog.
TIA standards committees reflect the competitive alignment, based on the troika of radio technologies. TR-45.1 defines analog standards (including NAMPS and the analog compatibility mode used by both TDMA and CDMA). TR-45.3 defines TDMA digital standards (IS-54 and IS-136) and TR-45.5 defines CDMA digital standards (IS-95). You can bet that if TR-45.5 comes up with a cool idea, TR-45.3 will have their own version no later than their next revision (and vice-versa).
So, now you’re sitting on my knee, you have to choose from the TDMA gifts on my left or the CDMA gifts on my right. Oh my, did I forget the little analog sack? Now where did that get to?
TIA standards subcommittee TR-45.5 is balloting their next generation CDMA standard as ANSI standard TIA/EIA-95-B. It will support calling name presentation (and you thought calling number was neat!). When roaming, CDMA phones will be able to display an indicator of the type of roaming partner (e.g. from “Premium” with the best roaming arrangements, down to simply “Available” for the least desirable roaming arrangements). Plus, unknown to consumers, the system will have enhanced abilities to redirect the phone to the best available system. Data will be supported at speeds up to 64 kbps. Even the government should be happy, through support for the PACA feature (Priority Access and Channel Assignment). That will allow priority users to have first call on idle channels during times of severe overload, and can also be used to give 9-1-1 calls priority over regular calls. And, for wireless local loop, CDMA will better emulate the capabilities of a copper loop (such as different ringing styles and meter pulses for billing). A similar feature, although applicable to mobile uses of CDMA, is to better emulate the duration and other parameters of DTMF tones, to ensure access to services that are fussy about such things.
CDMA is also revamping its identifiers. IMSI (International Mobile Station Identity) will be fully separated from MIN, to enhance international roaming. The Mobile Directory Number will be also separated from the MIN (although its only use in a phone is for display purposes) to better support wireless local number portability.
The TDMA elves have also been busy. TIA standards subcommittee TR-45.3 has been working on an ANSI standard that will be called TIA/EIA-136 Revision 0 (not to be confused with interim standard TIA/EIA/IS-136 Revision 0!). TDMA services come with better acronyms than CDMA. There is TSAR, for example. Not the Russian royalty, but Teleservice Segmentation And Reassembly, that will allow longer short messages to be delivered to a mobile (the current limit for both technologies is just over 200 characters, due to SS7 network limitations). This is accomplished by breaking the message up into pieces that are smaller than 200 characters (segmentation) and gluing them back together in the mobile (reassembly). GUTS (Generic UDP Transport Service) will allow arbitrary internet protocols (and therefore, applications) to be extended out to a mobile phone. And, since this column is being written near Halloween, let’s not forget BATS – BroadcAst TeleService transport. One new international roaming enhancement (without a clever acronym) is “+” code dialing. International roamers, instead of having to dial the local international access prefix (e.g. “011” in North America), can press a “+” key before the international number. So, +1-403-555-1212 would work in Mexico, Hong Kong or even up here at the North Pole.
Some features are being developed for both digital technologies (although the acronyms are usually different). Short message service, for example, is being enhanced for both TDMA and CDMA to allow one radio message to simultaneously carry the same short message to all mobiles that have the capability of receiving it, within the broadcasting cellsite, or to a subset of mobiles (based on the category of message). There is some interest in using this capability to extend the emergency alert system that currently can broadcast over radio and TV stations in the event of a hurricane, earthquake or unidentified flying reindeer (ho, ho).
Analog is further behind in the development of new services, but is not completely left out. The latest version of the analog standards EIA/TIA-553-A and TIA/EIA/IS-91-A will support sleep mode, which will extend the battery life of analog phones. The plans for the next generation of standards (EIA/TIA-553-B and TIA/EIA/IS-91-B) include IMSI, to better support international roaming.
One of the biggest problems faced by standards engineers is compatibility with older phones and base station equipment. With digital systems, the control channel structures are newer and more flexible, allowing older mobiles to ignore messaging supporting new features. However, for carriers, this still means that new features requiring radio interface modifications are unlikely to be available to people with older phones. This makes features that can be implemented with network modifications more attractive when carriers want existing subscribers to purchase the service. However, this is not a problem if the new service is bundled with a phone, or is intended to stimulate the sales of phones. An example of this is the AT&T Digital One Rate plan that requires a dual-band TDMA phone. This ensures that customers on this plan will always use AT&T spectrum if it is available in the roaming service area, and therefore minimizes the roaming charges that AT&T must absorb.
Analog has a bigger problem with compatibility, which partly explains the smaller list of new features. The analog control channel has to be compatible with existing AMPS, NAMPS, CDMA and TDMA phones (which all use this control channel when operating in analog mode), some of which did not implement the forward compatability provisions of older standards correctly, and thus have trouble when modifications to the control channel are introduced. Carriers are also less enthusiastic about implementing new analog features, because digital is being used as a way to differentiate their services. Enhancing analog would provide their competition with new services as well as themselves.
Well, I hoped you have picked your gift. It’s time for the next in line. Merry Christmas!
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