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IS-95: Progress, Performance and Prospects
By Jack Scanlon

Jack Scanlon, General Manager of Motorola's Cellular Infrastructure Group talks to CDMA Spectrum about the achievements of the IS-95 standard, the challenges it faces and the opportunities for CDMA in the wireless local loop market.

 

CDMAS: Do you have any views as to how Qualcomm is going about licensing IS-95 and do you exert any minimal or substantial influence on the way they're going about licensing it?

Jack Scanlon: I don't have the details of what Qualcomm's doing. I simply note that they've signed up a lot of licensees. We signed licence deals a long time ago back in 1990 before CDMA was recognised to the extent that it is today. We also have our own intellectual property in CDMA. As far as any leverage is concerned, it's a little different when it comes to the subscriber side of things. Anybody who is manufacturing dual mode CDMA/analogue phones has to come to Motorola because we have a lot of our own intellectual property in that area. So it's not just about how Qualcomm licenses things. If there's a second licence, then most vendors have to get it out of Motorola.

CDMAS: In the case of the IS-95 networks that are up and running in Korea, Hong Kong and U.S., it's generally held that the voice quality is either as good or, in some instances, better than that which can be attained on any other digital wireless network. As regards the spectrum efficiency claims for IS-95 CDMA, it's also generally accepted that the networks aren't fully loaded enough to be able to tell yet how they perform under heavy loading. Do you accept that that's the case and if you do, from what point in time do you think we'll really be able to see for a fact that IS-95 is more spectrum efficient?

Jack Scanlon: I agree with the first two comments. I disagree with the third. Let's look at what loaded means in an RF situation. Loaded in an RF situation has nothing to do with the total number of subscribers in the network. You can build a network covering, let's say, all the UK and a million subscribers, and still prove nothing about the capacity of the technology. The important thing is number of subscribers per MHz per cell site that you can point to. And that's where you're going to stress the RF. That's where issues of interference are going to be generated.

All you've got to do is go and look at Hong Kong which is already at more than 70,000 subscribers in one carrier 1.25 MHz per cell. You will find very few other networks in the world that can support 70,000 subscribers in 1.25 MHz. If you do the arithmetic, that says that Hong Kong is already performing at about 10 times AMPS at the moment. So we've already passed that point. Now how do we feel about that, how's it performing? It's performing exactly as our simulations predicted it would. We are now confident that CDMA in a mobile-and I underline mobile-environment in a difficult radio environment like Hong Kong-is about 10 times AMPS. We're also confident that in a fixed environment-if you take the terminal and nail it to a wall-you can come close to doubling that.

What's the evidence that operators believe this? Well, one is that Hutchison can be seen doing it in Hong Kong. The other evidence is that in Japan CDMA would have had no chance unless the operators-who, let me tell you, are really demanding technicians-were absolutely convinced that they could get sixteen to twenty times AMPS. And the reason for that is that PDC at six sector is already running at somewhere around 8-9 times AMPS. You get no benefit. That's why we introduced six sector and used the EVRC coder over there. If you're a ten mobility and you go to six sector you get about a 1.7 bang in capacity. So where we're at ten in Hong Kong and we go to six sector in Japan, we'll get to about 17. And that wasn't just based on a bunch of pen and pencil studies. That was based on thorough evaluation by the customer. So that's the evidence. Anybody who's still sitting around saying CDMA is all going to blow up must be smoking dope.

CDMAS: Among all the different wireless infrastructures, what proportion of global sales are currently going to CDMA?

Jack Scanlon: If you look at the 1996 contract awards, GSM accounted for $10.4bn or around 50% of the total. CDMA was $5.7bn so it's already running at about 30% of the contracts.

CDMAS: How does the IS-95 standard compare now in terms of the capabilities for interworking between vendors and in terms of international roaming capabilities? How advanced is the IS-95 standard in relation to what can be achieved with GSM today?

Jack Scanlon: There's no question that GSM has a superior roaming capability to any other technology, period. The smart card and the MAP protocol roaming arrangements for GSM have set the benchmark for everybody else to grab. Now in IS-41 environments like the US, you have the same deal. I can go anywhere in the US and use my AMPS phone or my CDMA phone on IS-41. What hasn't been done very successfully yet is the international IS-41 agreements. It's not the technology, it's getting the roaming agreements up and running. And that's what has to happen here with so many AMPS operators going to CDMA on a world-wide basis. Now another reason that never happened under AMPS was, frankly, that AMPS was kind of spotty where it went outside the US. If you look at Asia, for example, it only went into a few countries. But if you compare that to the number of places where CDMA is going now, there's much more momentum to solve this problem. It's now down to the operators to get together, as they do in the GSM community, and come up with the roaming deals.

CDMAS: What about inter-working between vendors?

Jack Scanlon: That's not a problem. There's a good spec on it. IS-41 is a very well known, nailed-down, spec. There are revs of it. I think the next one is rev c. There are certification processes as there are with MAP. I don't see a difference there at all.

CDMAS: What about in terms of advanced features and value-added services? How advanced is IS-95 and how much more work needs to be done to bring it up to the very best standards?

Jack Scanlon: There I think it's very close to parity. If you say `what's actually in the field?' of course GSM is ahead because it started in 1992. But if you ask what's in the spec, or equivalent, I'd expect CDMA to look pretty close to those capabilities in the 1998 timeframe.

CDMAS: The CDMA Development Group (CDG) is currently made up of a mixture of operators and manufacturers. As the number of CDMA operators grows, is there going to be a need for an operator-only association modelled on the GSM MoU Association or do you expect that the CDG will continue to serve as the primary vehicle for taking the industry forward?

Jack Scanlon: I think the CDG is fine. I think it's been effective in doing for CDMA what the MoU does for GSM.

CDMAS: Are you happy with the volume of CDMA handsets that appear to be in the pipeline or are you a bit concerned that there are going to be operators that have networks but no handsets?

Jack Scanlon: Well, I'm happy with what I see in the pipeline but I'm not happy with what's available today. Motorola's just now delivering, Samsung's delivering, Qualcomm's delivering and some new guys are coming out. Nokia's supposed to be coming out and some other Asian vendors are coming out with product as well. Certainly the operators are struggling to get adequate handset supply and struggling to have enough vendors to generate a proper competitive environment. If you look at how fast these subscriber vendors are coming out, I don't think we're going to get this problem behind us until the end of the year. But one thing worth remembering is that we saw exactly the same model develop in the case of GSM. This kind of thing is going to rise with the roll out of any new technology.

CDMAS: If you look at the first CDMA network rollouts in Hong Kong, Korea and the United States, there were inevitably teething problems of the kind you've referred to on the subscriber side. In the case of newly licensed operators who are considering IS-95 CDMA as a technology, are you able to assure them that the number of network glitches they incur will be substantially less than those you've encountered in your first roll-outs in the U.S. and Hong Kong?

Jack Scanlon: Most definitely. I look at all the performance statistics for a lot of networks all over the world and I can tell you that the best performing digital networks I see are these networks. What I mean is that if you look at the percentage of successful originations and the percentage of dropped calls, these networks are performing significantly better.

Let's look at it in terms of timescales. If you look at the quality that was being got from the TDMA or GSM networks after six months, I'm saying that on an absolute basis the CDMA networks are performing better than any other digital networks regardless of the time. If you take the factor of time into account, it may be significantly ahead.

CDMAS: How many frequency bands has CDMA been deployed in so far?

Jack Scanlon: I already see it being deployed at five different frequencies-1.7GHz in Korea, I.9GHz and 800MHz in the United States and at TACS and J-TACS frequencies. This is the first time I've ever seen a technology like this get requests for five frequencies. I've seen two before but this is the first time I've seen five. I think we'll see even more, though. We'll see CDMA deployed at frequencies that nobody's even guessing at today. By the way, we're the only guys to have our products at those five different frequencies.

CDMAS: The CDMA infrastructure orders that have been placed so far have been heavily weighted in favour of mobile applications but do you expect a shift in proportion over to wireless local loop and, if so, over what timeframe?

Jack Scanlon: I think we'll start to see major wireless local loop orders for CDMA this year. If you ask `why has it taken so long?', that's not a function of the technology because CDMA is just a good match for that kind of application. The problem is more one of the regulatory situation. It's going to be the new entrepreneurial operators that have no investment in wire that are going to push wireless local loop and that is just starting to happen. That is going to be the controlling factor because an incumbent operator has a lot of investment in copper. I think in India, in particular, we'll see some major progress this year.