CDMA Technology
Members Sign-In
You Can Have it All

By Perry M. LaForge
Executive Director, CDMA Development Group

Portuguese

Popular wisdom says that you can't have everything, but instead must make choices and trade-offs. Looking at what an operator wants out of a third generation solution (3G), one might say that it is an ideal list of requirements, not one that can be easily or reasonably achieved. The operator's wish list would include:

  • cost-effective solutions that build on infrastructure already in place, preserving investments
  • increased voice capacity and data speed in a single upgrade that can be deployed in second generation (2G) spectrum
  • standard systems, backwards and forwards-compatible with the wireless network and easily integrated with other networks and data platforms
  • rapid deployment in terms of market availability and implementation time frame
  • flexibility to upgrade in line with market demand

There is one 3G solution that does actually meet all of these requirements-CDMA2000. It is in fact the only 3G standard that has all of the qualities operators' demand for a migration that is technically and economically sound. The fact that CDMA2000 is evolutionary from a proven technology, cdmaOne, builds the operator's confidence level.

cdmaOne is known for its ability to offer coverage, voice clarity and capacity advantages over other technologies. CDMA offers today's operator significant capacity gains over TDMA or GSM. CDMA2000 will increase that benefit in the next generation. The first phase of CDMA2000 (1X) offers a doubling of capacity and will be ready for commercial deployment in 2000. Worldwide cellular and PCS operators can implement this 3G solution on their existing networks. There is no need to acquire new spectrum or to have clear spectrum in the existing bands to reap these capacity and other 3G advantages with CDMA2000.

It is easy to pass over this last statement without realizing the implication of it. Some may not even realize that other 3G solutions require new spectrum. Knowing that spectrum is a scarce resource and that existing operators have paid enormous amounts for that resource, it is of vast significance that 2G spectrum will be efficiently utilized to support more users and deliver the next generation of services with CDMA2000. It also ensures that the operators that migrate will remain competitive in the next generation by being able to offer the same range of services as the 'new' 3G operator at a lower cost. It does not make sense that those that pioneered wireless be penalized by the very fact that they are in the market today. CDMA2000 is therefore designed to remove any such barrier, allowing 2G operators a clear path to the future.

To ensure that the benefits of CDMA2000 reach all of the world's operators, the Third Generation Partnership Project 2 (3GPP2) is working to ensure that the principles of harmonizing 3G standards supported by global operators are reflected in the standards.

Hooks and extensions
3GPP2 is a group that includes the Association of Radio Industries and Businesses (ARIB), Japan; the Telecommunication Technology Committee (TTC), Japan; China Wireless Telecommunication Standard (CWTS) Group, China; the Telecommunications Technology Association (TTA), Korea; and the Telecommunications Industry Association (TIA), United States. Gerard Flynn of Bell Atlantic Mobile co-chaired the 3GPP2 September workshop that brought together 100 wireless industry representatives from 15 countries involved in 3G wireless standardization. The workshop focused on identifying hooks and extensions necessary for CDMA2000 operation on GSM networks. Flynn stated that he was "pleased that the workshop was making real progress due to the technical expertise and serious commitment of the participants". The international representation evident in the 3GPP2 and the harmonization work it is undertaking underscore the global nature of CDMA2000 and its importance in the 3G market.

The 1X capacity enhancements and its time to market have made it attractive to operators and the analyst community alike. High-speed data and the futuristic capabilities it enables may sound good in industry discussions and promotion, but the bottom line driving decisions for moving forward with 3G will always be financials. Recently in an article in RCR discussing migration strategies, Tim Luke, global wireless equipment analyst with Lehman Brothers, commented on the 1X advantage. "The challenge is the capacity issue," he said. "The cost perspective and performance is a positive for 1X and CDMA operators. That is why we are so bullish on CDMA." In the same article, Jon Dorfman, consultant with The Strategis Group, who is working on a study that details the business case of all the proposed technologies, weighed in for CDMA. "I'm a firm believer that CDMA makes a more viable business case going forward than GSM," said Dorfman. "The primary reason is that CDMA gives you huge voice capacity as opposed to GSM EDGE. When CDMA carriers upgrade, they can do it just for voice reasons. They see it as getting data for free. On the GSM path, it's much more of a commitment to data." Voice capacity may not catch headlines as readily as other features of 3G, but the reality of wireless is that voice capacity is the main driver for early adopters of 3G. In Japan-regularly noted as the first market in the world that will deploy 3G-the motivator is voice capacity to support a large and growing subscriber base, not bandwidth for advanced multimedia applications. Another point to note is that the likely operators to first deploy 3G in Japan are the cdmaOne operators DDI and IDO. These operators are already trialing 1X on their cdmaOne networks and the commercial version of 1X will be available ahead of any other 3G solution.

Financial benefits come from CDMA2000 attributes above and beyond its coupling of enhanced capacity and data speed in one upgrade and its first-to-market status. The fact that migrating to CDMA2000 capitalizes on a proven technology and existing capabilities, requires minimal network architecture modifications and incorporates standard Internet Protocol (IP) components, results in tremendous cost savings over other technology upgrade paths.

Today's cdmaOne handsets incorporate standard IP, and cdmaOne networks use IP addressing without an additional IP layer being added to the packet transport layer. This 2G design results in a high degree of backwards and forwards hardware compatibility as network operators implement new higher-speed data services and evolve to IP-based 3G standards. The cdmaOne packet data implementation utilizes standard routers, known as the Inter-working Function (IWF). The IWF is the same one used in the landline Internet. Going beyond platform compatibility to application development, professionals skilled at programming for the Internet can transfer that knowledge to applications for cdmaOne and CDMA2000. Incorporating industry standard components results in cost savings from lower capital investment requirements, rapid deployment and interoperability with other networks.

On the capital investment side of this equation, CDMA2000 yields incredible savings. 1X implementation only requires software upgrades to the Base Station Controllers (BSC) and Base Transceiver Stations (BTS), not replacement of infrastructure equipment. On the handset side, chips are already announced to support 1X, and handsets for cdmaOne and CDMA2000 will be backwards and forwards compatible.

The 2G handset will operate on the 3G network and in turn the 3G handset will be able to access the 2G network. This transparency for users and ability to roam seamlessly across the 2G and 3G platform gives the operator a large degree of flexibility in deployment timing and effective resource utilization. Segments of the network can be upgraded where capacity enhancements or higher data speeds are essential without requiring that other portions lacking this demand be upgraded unnecessarily. For both national and international roaming, an operator does not have to consider the upgrade plans of other operators in assessing whether a CDMA2000 user will have any service outside the home area since the 2G network access will always be available.

Evaluating all of the facts proves that CDMA2000 meets the operator's 3G requirements wish list. Previously wireless systems were evaluated in terms of the three Cs: capacity, coverage and clarity. With the migration to 3G we should expand that to five Cs, adding cost and compatibility to the model. It is clear to see that with CDMA2000, operators have a "rational" migration path.

Parameters PCS-1900 (GSM) PCS-1900 (GSM) PCS TDMA PCS TDMA PCS TDMA CdmaOne EVRC
Frequency Reuse (3-sector) K=4 K=7 K=5 K=7 K=9 K=1
Spectrum Allocation (including Guard Bands) 15MHz Rx 15MHz Rx 15MHz Rx 15MHz Rx 15MHz Rx 15MHz Rx
Carrier Bandwidth 200kHz 200kHz 30kHz 30kHz 30kHz 1.25MHz
Number of Effective Carriers per Sector 6 4 33 24 19 11
Number of Voice Channels per Sector (*excluding control channels) 45 (=6x8-3*) 29 (=4x8-3*) 97 (=33x3-2*) 71 (=24x3-1*) 56 (=19x3-1*) 220 (=20x11)
Number of Erlangs per Sector (2% blocking) 35.6 21.0 85.1 60.1 45.9 143
Spectrum Efficiency (Erlangs/Sector/MHz) 2.4 1.4 5.7 4 3.1 9.5

 

System Component cdmaOne 95A cdmaOne 95B CDMA2000 1X CDMA2000 3X
Handset 95A handsets will work on all future networks 95B, 1X and 3X at 14.4Kbps 95B handsets work on 95A networks at 14.4Kbps and 95B, 1X and 3X systems at 64Kbps 1X handsets will work on 95A networks at 14.4Kbps, 95B networks at 64Kbps and 1X and 3X networks at 144Kbps 3X handsets will work on 95A networks at 14.4Kbps, 95B networks at 64Kbps and 1X networks at 144Kbps and 3X networks 2Mbps
Infrastructure Standard New software in BSC New software in BSC and channel cards at base station Backbone modifications new channel cards at base stations
Data Speed 14.4Kbps 64Kbps 144Kbps 2Mbps