Get Here about CDMA technology and How CDMA Works, CDMA Solution and CDMA RF Optimization.
• Definition: Orthogonal functions have zero correlation. Two binary sequences are orthogonal if the process of “XORing” them results in an equal number of 1’s and 0’s. Example: 0000 (XOR) 0101 —— 0101 • Generation Sequence: – Seed – Repeat: right & below – Invert: diagonally The above table of … Read more
Dsss – Direct sequence spread spectrum DSSS – Direct Sequence Spread Spectrum is a spread spectrum technology in which original data is expand using PN code randomly to reduce noise and this also provide high security to data as is scrambled data. Spread spectrum technology spread spectrum technology used in CDMA and Cdma is a … Read more
Here I write about EVDO (HSD) reverse channel in short or summarize defination. The EVDO channels for the reverse connection have a similar structure as for CDMA2000. The reverse link for 1xEV-DO has a structure similar to that for CDMA2000. In EV-DO all signalling is performed on the data channel and this means that there … Read more
A number of channels are transmitted in the forward direction to enable signalling, data and other capabilities to be handled. These channels include the Traffic channel, MAC channel, Control channel and Pilot. These are time division multiplexed. Traffic Channel – This channels uses Quadrature Phase Shift Keying (QPSK) modulation for data rates up to 1.2288 … Read more
The forward link possesses many features that are specific to EV-DO, having been optimised for data transmission, particularly in the downlink direction. Average continuous rates of 600 kbps per sector are possible. This is a six fold increase over CDMA2000 1X and is provided largely by the ability of 1xEV-DO to negotiate increased data rates … Read more
The polarization is a radiation feature for indicating the vector special direction of field strength of electromagnetic wave. If unspecified, the spatial direction of electric field vector usually serves as the polarization direction of electromagnetic wave. The spatial direction of electric field vector is the direction of maximum radiation by antenna. The electromagnetic wave of … Read more
Search Window in cdma is essential parameter to work cdma technology because based on search window as defined in system mobile needs to take important decision for available bts. Search window play main role in mobile switch on, handoff, access etc. let’s check in detail. Why Search Window? A CDMA system employs the synchronized detection … Read more
Here I write about Pseudo-Noise Code and what its use Pseudo-Noise Code its two type and Pseudo-Noise Short code is identification for each BTS and Pseudo-Noise Long Code is Identification of each user. Let’s understand basic. A pseudo-noise code (called PN code in short) has properties similar to a noise sequence. It is actually a … Read more
If it is available, the second cell site returns the Walsh Code that will be assigned for the soft handoff. At this point, the original base station orders the soft handoff by using a handoff direction message on the traffic channel using one of the two types of signaling: dim and burst or blank and … Read more
Once a call is established, the mobile is constantly searching for other possible cell sites that might be good candidate for soft handoffs. Most of the search time is limited to looking for those PN offsets specified in the neighbor list found on the paging channel. The rake receiver’s searcher is the device that scans … Read more