Principles of Cellular Telephony Advanced Mobile Phone Service AMPS Bellevue Community College Bob Young, Instructor

AMPS Advanced Mobile Phone Service

Terminology Common terms and abbreviations

MTSO Mobile Telephone Switching Office Later, called the MSC, or Mobile Switching Center

Cell Site Later, called the base station

The Phone Mobile Mobile Station Portable Handset

Digital Signaling Frequency Shift Keying: +/- 8KHz 10 Kbps rate Primarily on control channel Secondarily on voice channel

Supervisory Audio Tone SAT 5970 Hz 6000 Hz 6030 Hz Originates from cell site Repeated back by handset

Signaling Tone ST 10 KHz Originates from handset

Downlink From the cell site to the mobile Imagine looking down from the tower Forward link

Uplink From the mobile to the cell site Imagine looking up from the handset to the antenna on the tower Reverse link

Preparing Audio Signals Compander -- 2:1 compression Pre-emphasis -- 6 dB per octave Limiter -- limits amplitude so deviation won't exceed +/- 12 KHz peak to peak Low pass filter -- audio cutoff at 3KHz Inject the Supervisory Audio Tone (SAT) No vocoder

Mobile Identifiers Mobile Identification Number (MIN) (phone number) Electronic Serial Number (ESN) unique to each phone Station Class Mark (SCM) identifies phone features and capabilities to the system

System/Base Station Identifiers System ID (SID) Supervisory Audio Tone (SAT) Digital Color Code (DCC)

Channels Forward Control Channel (FOCC) Reverse Control Channel (RECC) Forward Voice Channel (FVC) Reverse Voice Channel (RVC)

Handoff Controlled by the base stations and MTSO "Break before make" Between cells or sectors Between systems "Blank and burst" signaling on FVC

Channels 832 Channels 416 channels per carrier (A & B) 21 control channels per carrier 395 voice channels per carrier Channels are &

Carriers A = was non-wireline B = was wireline Now you can own both, but only one in a market.