Today's networks support Internet applications such as e-mail, web browsing and access to corporate intranets as well as digital fax and other "mobile office" functions at 14.4kb/s. The evolution of cdmaOne networks to support cdma2000 Phase I capabilities provides for enhanced network performance in a number of areas, including speed and efficiency of data transmission.

Today's CDMA voice and data services are provided with IS-95-A infrastructure and subscriber equipment. CdmaOne networks provide both packet- and circuit-switched data services at speeds up to 14.4kb/s along with a choice of 8K, 13K and 8K EVRC voice services from the same platform. This is one of the primary benefits of the network design: Carriers don't have to make significant investments to add data services to voice. Typical circuit-switched applications include both analog and digital fax and file transfers, and Internet connections and e-mail delivery are popular packet-based applications.

HDR & Cdma2000 Phase I

High data rate (HDR) and cdma2000 Phase I are complementary technology developments that offer higher capacities, better use of spectrum, higher speeds and additional services. As the first part of the development and standards effort for cdma2000, cdma2000 Phase I gives you the ability to double the capacity, or spectral efficiency, of current cdmaOne networks. Also, it expands capabilities to allow packet and circuit data services at speeds up to 144kb/s.

Carriers that want to offer peak data rates of greater than 1.8Mb/s or that want to offer data services to a large number of customers without diminishing voice capacity soon will be able to implement this data feature that uses a standard-band 1.25MHz carrier. HDR was first demonstrated publicly in September 1998, and field trials are scheduled with US West and Cisco Systems in early spring of 1999.

Circuit Vs. Packet

HDR is designed to optimize packet-data services. It separates data service from voice service because the two have fundamentally different requirements. Voice services are real-time, delay-sensitive applications that aim to provide equal service to all users, regardless of their location in the cell. This results in power-sharing schemes -- where weaker users are allocated more power than stronger users -- being the optimal solution for voice. A relatively modest data rate is sufficient for high-quality voice service, and voice users cannot benefit substantially from higher data rates. Physical layer designs for both voice and data services must make compromises in their design features (including choice of frame sizes, control and signaling methods, and delay budgets) to accommodate both services.

On the other hand, packet-data systems are aimed at maximizing the sector throughput. Because data users have various data-rate requirements, the goal is to allocate each user the maximum data rate that he can accept, based on his application needs and the wireless channel conditions.

Circuit-switched networks establish an end-to-end channel capacity for data transmission just as they do for a voice call. While the channel is in use, no other user's data can be transmitted. The user has exclusive control of the channel.

Packet-switched networks break messages into small data packets and send each packet over the network with a destination address. These networks are referred to as "connectionless" because there is no end-to-end fixed connection. The Internet is a packet-switched network that shares the channel capacity. Packet-switched networks allow multiple users to share the same channel at the same time. This allows a smooth transition for packet-based networks, such as HDR, to offer high-speed Internet access.

Improvements

In early 1999, TIA plans to publish a draft standard for its cdma2000 (also known as 1XRTT submission, cdma2000 Phase I or "95-C") proposal, supported by the CDMA Development Group and a coalition of wireless-equipment manufacturers. Cdma2000 uses a standard-band 1.25MHz carrier but doubles the capacity of current cdmaOne systems and offers other enhancements such as even wider coverage and longer standby times. It also provides a high degree of backwards compatibility with today's cdmaOne infrastructure, handsets and services.

The Enhanced cdma2000 standard (also known as 3XRTT) is being defined by a broad-based group that includes the TIA and other industry organizations. This standard will satisfy the objectives of IMT-2000, including the following data requirements: 144kb/s for mobile use, 384kb/s for pedestrian use and 2Mb/s for fixed use. Enhanced cdma2000 can be deployed in new or current frequency bands with much backwards compatibility to cdmaOne and IS-41-based networks.

Leveraging Investments

Elements of the following cdmaOne products and capabilities can be reused under cdma2000:

* Radio access equipment

* Switching equipment

* Phones

* Features and services

* Network planning tools, billing systems, operations and maintenance centers

* IS-41 network processes.

Evolution to 3G does not require a complete change-out of technology, regardless of the networking infrastructure a wireless carrier has installed today. Options such as the cdma2000 1XRTT and HDR also will give carriers choices for implementing an air interface that can improve capacity and increase data speeds.

One of the main benefits of implementing cdma2000 for a 3G system is that the technology is not brand new. History has shown that it takes years to fully understand, implement and optimize new mobile technologies in the market. CdmaOne went from standards conception to implementation in about six years. The cdma2000 window should be even shorter because it is an evolution of an existing standard.

However, there are other benefits:

* The technology offers the ability to achieve higher data rates and increased spectrum efficiency using a 1.25MHz carrier and a 3.75MHz carrier. This will be critical to carriers that have 5MHz of spectrum or less but want to offer wideband data speeds and improve overall system-calling capacities.

* Cdma2000 offers higher capacity than other standard submissions for both voice and data.

* It supports three modes for pilot channels: common pilot, pilot per traffic channel and pilot per spot beam to allow for greater efficiency.

* The technology supports synchronization in the base-station transceiver to keep the subscriber unit costs to a minimum.

* Cdma2000 supports a sufficient number of Walsh codes to support wireless-local-loop applications in addition to mobility systems.

* It is compatible with both GSM-MAP and IS-41 networks.

* Cdma2000 supports a coherent reverse link for improved capacity.

* It supports a variable rate vocoder design for improved voice quality and capacity in CDMA networks.