CDMA

CDMA (Code Division Multiple Access) is a spread spectrum technology that allow multiple user to occupy same radio channel.

Characteristics:

- every user using unique code.

- Every data will be spreaded before it emitted so its enabling multiple access.

- Transmition bandwidth larger than information bandwidth. The ratio between of them is called processing gain (Gp).

- Interference insensitive

- Using soft handoff because all system using same frequency.

- Anti jamming.

IS-95 CDMA specification:

- bandwidth : 1.25 MHz

- chip rate : 1.2288 Mcps

- freq. uplink : 869 – 894 MHz 1930 – 1990 Mhz

- freq. downlink : 824 – 849 MHz 1850 – 1910 MHz

- frame length : 20 ms

- bit rates: 9.6 Kbps 14.4 Kbps

- speech code: QCELP 8 KBps, ACELP

GSM (Geser Sedikit Mati/Groupe Spécial Mobile/Global System for Mobile communication)

What is GSM? GSM is Global System for Mobile communication it’s a global standarditaion for digital mobile communication. Actually the GSM name is a group for standarditaion that built at Europe in 1982 to standardizing mobile cellular phone at Europe that operated on 900MHz frequency. GSM itself is originally abbreviation of Groupe Spécial Mobile.

There is 3 variant of GSM based on frequency band.

1. GSM900, work on 900MHz
2. GSM1800, work on 1800MHz
3. GSM1900, work on 1900MHz

Below is structure of GSM network

solaris top command

linux: top

solaris: prstat

:p