Is Verizon a CDMA or a GSM network?

Why is the network expansion of CDMA much fast/cheaper than GSM?

• (1) I have seen CDMA fixed phones lines. But I heard that it is a technology that should be used to mobile phones? If so why arent our mobile phones on CDMA? (2) How do you compare CDMA to GSM? They say setting up CDMA towers and expanding coverage over a large area is much easier, compared to GSM. Please explain (3) Whats 'spread spectrum communications' and how is it related to CDMA and GSM? thanks :)

• Answer:

  CDMA is a wireless method of allowing many people to communicate on the same channel. This is called multiple access or the "MA" part of CDMA. It should not be confused with the mobile phone standards called cdmaOne and CDMA2000 (which are often referred to as simply "CDMA" from Qualcomm). CDMA is a form of "spread-spectrum". Other forms of wireless multiple accesses are TDMA (time division) and FDMA (frequency division). To understand the analogy, you have many people in a room and they all want to talk. TDMA is only one talk at a time but at a small allotted time is allowed. FDMA is all talk at the same time but some uses a high pitch voice and other uses a low pitch voice and each train their ears to ignore the other pitches. CDMA being a spread spectrum, everybody talks at the same time but uses a different code set, sort of like different languages. However the talking is repeated many times. By repeating many times you can make out the whole sentence. CDMA is not exactly repeating but a long string of code is used to represent a short information code and long string of codes can be jammed and still make out the information. Other forms of CDMA besides the Qualcomm's cdmaOne and CDMA2000 are the Global Positioning System (GPS) and WCDMA (which is the none-Qualcomm version of 3G). GSM is the none-Qualcomm version of 2G and is based on TDMA. Other forms of TDMA is DAMPS and Nextel's iDEN or DECT cordless phone standard. There are fixed version of both cdmaOne and GSM or other forms using CDMA or TDMA. The only difference between fixed and mobile is that there are no cell site handoff, which mean that the fixed phone will work only within one cell site. If travel far away enough from the cell site, the call is drop. Cell sites are about 1 mile apart, depending on buildings and terrain. 2G and 3G; what are they? 2G provides voice and slow Internet access of equivalent speed to dialup, while 3G also does voice but can provide Internet access at DSL or Cable Modem speeds, while you are mobile (driving at 100 miles per hour.) There are 2 major completing standard groups: 1. 3GPP - this is the miss-named GSM to most people. 2G is supported using TDMA with GSM standard. Thus the GSM misuse. 3G is supported using CDMA with WCDMA standard. Thus a 3G mobile phone is actually 2 phones in one using both TDMA and CDMA. Nevertheless people still call this 3G GSM, which is incorrect. 2. 3GPP2 - this is the Qualcomm completing standard to 3GPP. 2G is supported using CDMA with cdmaOne standard, and 3G also uses CDMA with CDMA2000 standard. Thus the upgrade for networks that started out using cdmaOne (Verizon and Sprint) from 2G to 3G capability took place sooner as the upgrade only involved changing out circuit cards. The upgrade from 2G to 3G for 3GPP is not as easy as it involved adding additional racks of equipment. AT&T and T-Mobile are service providers here in USA.