Cdma lecture notes pdf

In fact, many different "signals" baseband with different spreading codes can be modulated on the same carrier to allow many different users to be supported. Using different orthogonal codes, interference between the signals is minimal. Conversely, when signals are received from several mobile stations, the base station is capable of isolating each as they have different orthogonal spreading codes. The following figure shows the technicality of the CDMA system.

During the propagation, we mixed the signals of all users, but by that you use the same code as the code that was used at the time of sending the receiving side. You can take out only the signal of each user. This means, CDMA operates in the presence of noise and interference. In addition, neighboring cells use the same frequencies, which means no re-use. So, CDMA capacity calculations should be very simple. No code channel in a cell, multiplied by no cell.

But it is not that simple. Although not available code channels are 64, it may not be possible to use a single time, since the CDMA frequency is the same. CDMA is a spread spectrum technique. Each data bit is spread by a code sequence. This means, energy per bit is also increased. This means that we get a gain of this.

Half Duplex System: Communication systems which allow two-way Communication by using the same radio channel for both the transmission and reception. At any given time the user can only either transmit or receive information. Handoff: The process of transferring a mobile station from one channel or base station to another. Wireless communication System Definitions.

Mobile Station: A station in the cellular radio service intended for use while in motion at unspecific locations. Mobile Switching Center: Switching Center coordinates the routing of calls in a large service area. Reverse Channel: Radio channel used for transmission of information from the mobile to the base station.

Multicarrier Modulation: Use many parallel channels, each with a low data rate, e. Stubblefield of Murray, Kentucky. In , such as Mobile Telephone Service, were not cellular, and so did not feature "handover" from one base station to the next and reuse of radio frequency channels.

May Patent to Charles A. Gladden and Martin H. Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines.

Explore Podcasts All podcasts. Core Network. Reverse Link Channels. Duplexing Method : Frequency Division Duplexing. Access Channel per carrier: Maximum 61 Channels. RF Spacing: - 1. Coverage: - 5 Km with hand held telephones and approx. Billing and Customer Care System. Welcome Back. Continue with Google. Continue with Facebook. Forgot Password? New User? Sign Up.