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To: gdichaz who wrote (27499)	7/9/2000 10:31:16 AM
From: Eric L	Read Replies (2) \| Respond to of 54805

Cha2, Re: QCOM - WCDMA & cdma2000 - descriptions from Intel There is a pretty good recent article on the Intel Developers site called The Evolution of Third-generation Cellular Standards. An 8 page HTML version is here: developer.intel.com A PDF version is here: developer.intel.com The article discusses the Mobile/Cellular Standards Process and the various Standards Development Organizations involved. It also describes the differences between WCDMA & cdma2000: >> Wideband Code Division Multiple Access (WCDMA) should not be confused with narrowband CDMA; they are completely different protocols. WCDMA is a younger technology, defined specifically to deliver high-speed data services and Internet-based packet-data at 3G data rates. WCDMA supports both packet and circuit-switched communications, such as Internet access and landline telephone services; however, WCDMA was defined with no requirements on second-generation backward compatibility. WCDMA makes very efficient use of the available radio spectrum. No frequency planning is needed, since one-cell re-use is applied. Using techniques such as adaptive antenna arrays, hierarchical cell structures, and coherent demodulation, network capacity can be increased. In addition, circuit and packet-switched services can be combined on the same channel, allowing true multimedia services with multiple packet or circuit connections on a single terminal. WCDMA capacity is approximately double that of narrowband CDMA. The wider bandwidth and the use of both coherent demodulation and fast power control in the uplinks and the downlinks allow a lower receiver threshold. WCDMA uses a network protocol structure (signaling) similar to that of GSM; therefore, it will be able to use the existing GSM network as the core network infrastructure. In CDMA2000, a range of RF channel bandwidths are supported: 1.25, 3.75, 7.5, 11.25, and 15MHz. This range allows for support of a range of data rates as well as a high number of users. In order to support higher bandwidth channels, CDMA2000 has defined two configuration options: Direct Spread (DS) and Multi-carrier (MC). The DS option is similar to IS-95B and uses the entire bandwidth to spread the data for radio transmissions. In the MC option, user data is encoded as a single stream and de-multiplexed into multiple streams. Each stream carries part of the user data using a different carrier frequency signal, hence the name Multi-carrier. The receiver will multiplex the received signals together before demodulation is carried out. Both the DS and MC options are available in the forward link only. The reverse link supports only the DS option. << BTW: I thought Dr. Jacobs presentation was excellent. - Eric -