5.1 The Digital PCS Standards


The digital PCS standards comprise an interim standard (IS), to indicate that the standard is not yet approved by the TIA/EIA (Telecommunication Industry Association-Electronic Industry Association). However, these standards have achieved the status of TIA/EIA standards but are commonly referred to with their "IS" code (e.g., IS-136).

As described in this chapter, the term IS-136 network refers to the cellular standard defined by the TIA for digital PCS networks. In particular, IS-136 identifies a particular part of the digital PCS family of standards and does not identify all the features of digital PCS networks. The IS-136 standard is the result of the evolution of the North American analog cellular systems called advanced mobile phone service (AMPS). Due to the phenomenal success of AMPS networks, the need for a more efficient system and more cellular capacity led to the development of a first digital cellular standard, called IS-54. However, IS-54 drawbacks (higher costs with no clear improvements for the end users) did not allow IS-54 to duplicate the success of AMPS. Therefore, the IS-136 standard was developed to allow for increased cellular capacity and for providing new services to mobile users. IS-136 allowed for a capacity three times larger than the one provided by AMPS, and for new features such as longer battery life, authentication and voice privacy, caller ID, message waiting indication, and short messages. Whereas AMPS systems used analog traffic and control channels, IS-54 introduced a DTC. Full-rate DTC is supported in IS-54 by means of time multiplexing of 30-KHz RF channels, and a mobile user is assigned a full-rate DTC. In addition to the DTC, IS-136 introduced the DCCH, which allows for the new features supported by IS-136 with respect to its predecessors.

The digital PCS standards comprise a set of standards including IS-136, IS-137, IS-138, IS-641, IS-130, and IS-135. Here we give a brief summary of each standard:

  • IS-136: Mobile Station-Base Station Compatibility Standard. IS-136 describes the channels used in digital PCS from the physical layer to the network layer, focusing in particular on the DCCH.

  • IS-137: Minimum Performance Standard for Mobile Stations. IS-137 defines the minimum requirements for the mobile station in terms of receiver, transmitter, and environmental requirements. Requirements for the receiver include frequency coverage, acquisition time, demodulation, bit error rate, and signal strength measurement accuracy. Requirements for the transmitter include frequency stability, power output, modulation type and stability, limitation of emissions, and time alignment. Environmental requirements include temperature, power supply voltage, humidity, vibration , and shock . The standard defines the minimum requirements and the method to measure them.

  • IS-138: Minimum Performance Standard for Base Stations. IS-138 is the companion standard to IS-137 and defines the minimum requirements for the base station in terms of receiver, transmitter, and environmental requirements.

  • IS-641: Enhanced Full-Rate Speech Codec. IS-641 describes the vocoder adopted in digital PCS.

  • IS-130: Radio Link Protocol. IS-130 defines the link layer used in digital PCS to support asynchronous data and fax services defined by IS-135 over an IS-136 DTC.

  • IS-135 : Asynchronous Data and Fax. IS-135 defines a network protocol for asynchronous data and fax transport that described call setup, monitoring, release, user data transport, and other features. IS-135 requires IS-130 as radio link and uses IS-136.

IS-137, IS-138, IS-641, IS-130 and IS-135 are supporting standards for IS-136. This means that they complement the features defined in IS-136 for the support of digital PCS services.

IS-136 standard merges the digital PCS family into a single standard composed of multiple parts in order to allow for easier tracking of standard modifications and for greater flexibility in the development of new features.



IP in Wireless Networks
IP in Wireless Networks
ISBN: 0130666483
EAN: 2147483647
Year: 2003
Pages: 164

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