30-09-2016, 04:00 PM
INVESTIGATION BASED ON ADJACENT COEXISTANCE ISSUES BETWEEN DDT AND 4G-LTE IN DDB
1457093192-veryimpnewabstract.docx (Size: 11.92 KB / Downloads: 8)
ABSTRACT:
With the introduction fourth generation long term evolution (or) 4G-LTE mobile services the user should see the data speed that are up to 10 times faster than the current 3G networks. Data uplink and downlink will be possible without having any buffering for 4G-LTE users compared to present 2G and 3G mobile services. From the spectrum organization point of view, the world is divided into three Regionsby the International Telecommunications Union (ITU): Region 1 (Europe and Africa), Region 2 (Americas) and Region 3 (Asia and Oceania). The first DD band (DD1), which is the amount of spectrum made available after the transition from analogue to digital terrestrial TV broadcasting, corresponds to the 800 MHz band (from 790 to 862 MHz) in Regions 1 and 3,and the 700 MHz band (from 698 to 806 MHz) in Region 2. Most spectrum regulators worldwide have already auctioned and awarded the DD1 band to fourth generation (4G) Long Term Evolution (LTE) mobile services. An impending problem when deploying mobile networks in the digital dividend bands is that interferences may appear in the adjacent radio frequency (RF) channels used for DTT. Possible solutions imply either an inefficient use of the spectrum, increasing the guard band and reducing the number of RF channels for DTT, otherwise an important cause of using anti-LTE for DTT receiver. the impact of the guard band and the use of anti-LTE filters have been studied, together with different LTE signal parameters such as traffic load, bandwidth, and interfering link (uplink and downlink). Lighter loads imply significantly larger time variations in the signal waveform, and hence worse interference protection ratios occur in general (up to almost 10 dB), and that is the reason why the LTE uplink generates more interference than the downlink. Result shows naturally, the LTE interferences depend on the level of the useful DTT signals, and hence potential coexistences issues have to be studied case by case, especially for DTT networks dimensioned for fixed rooftop reception.