Today wireless transmission of data is becoming more and more popular and the need for faster transmission rates is increasing. Since the bandwidth is limited it is important to try to use it to the fullest. CDMA is a technology that allows multiple accesses on the same frequency and time thus making it very bandwidth efficient. The CDMA technology was first introduced in the second generation?s cellular systems but has since then been improved and is reused in today?s 3G systems as Wideband CDMA.

This Masters thesis work describes a comparison between two different methods for estimation of the down channel (base station to mobile subscriber) in Wide-band Code Division Multiple Access (WCDMA). The first estimation method, Optimal Feed-forward Channel Estimation (OFCE), is a conventional method that bases the estimates on data that is known to both sender and receiver, so called pilots. The second method, Decision Directed Channel Estimation (DDCE), is an elaboration of OFCE. It also uses user data for estimation. Simulations show that DDCE, in comparison to OFCE, does not attain an improvement in signal-to-noise-ratio (SNR) for high bit error rates (BER).

This Masters thesis work describes a comparison between two different methods for estimation of the down channel (base station to mobile subscriber) in Wide-band Code Division Multiple Access (WCDMA). The first estimation method, Optimal Feed-forward Channel Estimation (OFCE), is a conventional method that bases the estimates on data that is known to both sender and receiver, so called pilots. The second method, Decision Directed Channel Estimation (DDCE), is an elaboration of OFCE. It also uses user data for estimation. Simulations show that DDCE, in comparison to OFCE, does not attain an improvement in signal-to-noise-ratio (SNR) for high bit error rates (BER). An improvement is only seen when the BER becomes much lower than what is common in real situations. In conclusion DDCE is complicated, involves many mathematical operations and gives insignificant improvement of SNR when BER takes common values. It is legitimate to question if it is possible to use the method in a real mobile phone system..

This report presents the results of the tests of data rate and signal strength that I have conducted. The tests have been performed in the municipality of Arvidsjaur, Sweden. The report also contains the conclusions I have drawn from the results as well as an introduction to radio and the technology used in the nets that have been testedThe equipment used is:LG G2 cellphone used to test Telias 3GHuawei b593s-22 3G/4G router used to test Tele2s 3G/4GMobile Broadband Gateway R-90 used to test Net1s CDMAThe data rate has been tested with bredbandskollen (www.bredbandskollen.se). The signal strength(RSSI) has been read in the configuration menu of the broadband routers as well as in the cellphone.The conclussions drawn:Net1s net appears to be more used compared to its capacity than the other netsTele2s net has a high and even data rate where it?s signal strength is sufficient.

This report presents the results of the tests of data rate and signal strength that I have conducted. The tests have been performed in the municipality of Arvidsjaur, Sweden. The report also contains the conclusions I have drawn from the results as well as an introduction to radio and the technology used in the nets that have been testedThe equipment used is:LG G2 cellphone used to test Telias 3GHuawei b593s-22 3G/4G router used to test Tele2s 3G/4GMobile Broadband Gateway R-90 used to test Net1s CDMAThe data rate has been tested with bredbandskollen (www.bredbandskollen.se). The signal strength(RSSI) has been read in the configuration menu of the broadband routers as well as in the cellphone.The conclussions drawn:Net1s net appears to be more used compared to its capacity than the other netsTele2s net has a high and even data rate where it?s signal strength is sufficient.