gsm
Cyclic vs. Random Hopping Sequences Both cyclic and random hopping modes are available in GSM. In the cyclic mode the frequencies are changed sequentially from the lowest frequency to the highest as defined in the MA-list. In random mode the frequency to be used for each burst is selected from the MA-list by a predefined … Read more
Effect of Interleaving In GSM the speech frame is transmitted over eight consecutive bursts. The fast fading causes bursty bit errors that degrade the efficiency of the convolutional coding. The interleaving is designed to spread these errors over longer time. However, the decoding performance is not significantly improved if consecutive bursts are exposed to the … Read more
In GSM System Losses is different type here i write about Losses by Duplexer, Body And Penetration Duplexer Loss A duplexer enables simultaneous transmission and reception of signals on the same antenna. It provides isolation between the transmitted and received signal. Duplexers typically have a insertion loss of 0.5 to 1 dB Body Loss For … Read more
When talk about Practical RF Planning then its also needs to take care about losses and physical losses like Cable,Connector and Combiner at BTS is more important. Cable Loss Two types of cables are used, main cable and jumper cable. Cable losses are given in per 100feet. Jumper cable has more loss than main cable. … Read more
Gain is most important thing in wireless communication and if its passive then it will be very useful here I write about antenna gain and diversity gain definition and its effect. Antenna Gains Mobile Station Antenna Portable mobile phones antennas have typically gain of 0 to 1 dBd. Car mounted antenna has a typical gain … Read more
When we talk about GSM Rf planning then first thing into mind is Link Budget,here i write about why link Budget analysis in GSM Link budget analysis provides: Coverage design thresholds EIRP needed to balance the path Maximum allowable path loss It is important that the uplink and downlink paths be balanced, otherwise not enough … Read more
Frequency Planning is possible by manually or automatic.At initial stage of new RF Network automatic frequency planned and then after for optimization based on KPI manual frequency planing done. Manual Frequency Planing Steps The steps to be followed in manual frequency planning are: Calculating the frequency reuse distance theoretically. Determining the cell repeat pattern Planning … Read more
Basically Diversity Antenna required because of Signal Rich at mobile or BTS by reflection and this change value of its level and quality either good or bed. Let’s understand in detail. NEED OF DIVERSITY In a typical cellular radio environment, the communication between the cell site and mobile is not by a direct radio path … Read more
In mobile communications two main categories of antennas used are Omni and Directional antenna here I write about antenna characteristics and use. ANTENNA TYPES Omni directional antenna These antennas are mostly used in rural areas. In all horizontal direction these antennas radiate with equal power. In the vertical plane these antennas radiate uniformly across all … Read more
Drive test is simply test of coverage for radiating BTS . from drive test you can imagine BTS coverage boundary and foot print of bad coverage and good coverage.lets understand dt basic. Drive Test Plan Each drive route should be marked on a detailed road map showing the exact route to be driven. These maps … Read more