In a wireless communication system, cooperative diversity can be used to combat fading effects. In cooperative di versity, the system uses idle antennas, which are located at different locations, as relays. Cooperative communication with OFDM is widely used in communication systems and it enhances communication performance of the system. There are different methods to enhance the performance of OFDM systems, carrier interferometry code is one of them. While, carrier interferometry code increase the performance of the system and also reduces PAPR level. Carrier interferometry codes can be implemented on an OFDM system by using FFT and wavelet. In this paper we investigate the effect of the relay position on the carrier interferometry cooperative OFDM system which uses wavelet transform. The effect of the relay position is investigated over different combiners and relaying strategies. The results show that, relay position effects the performance of the system and optimal location for the relay is right between source and destination.

No abstract

Kayseri is an important city located at the foot of Mount Erciyes, which is considered to be the center point of Anatolia. Kayseri has been the crossroads of important trade routes in all periods from Kültepe to the present day. Kayseri, has retained its charm during the Roman period and has become an important center. The monumental tombs, city walls and temple ruins dating from Rome to the present day show the importance of the Roman architectural movement in Kayseri. Cremation is an important burial tradition accepted in Rome. This tradition was popularized by mass tombs known as columbarium tombs. Columbarium tombs are mass burial sites that serve a particular public group. Koramaz Valley is a twelve kilometers long earthquake fracture which is located about twenty kilometers to the north east of Kayseri city center and contains many rock tombs, cave churches and villages in which life continues. Twenty-one columbarium tombs and three dovecotes in Koramaz Valley were investigated. In the first part of the study, general history of Kayseri is explained and then Koramaz Valley is mentioned. Later, Roman funeral burial methods are examined, especially cremation burials and columbarium tombs are discussed. Dovecotes and columbarium tombs are often confused, with the fact that almost all of the columbarium tombs were later converted into dovecotes. Consequently, the columbarium tombs of the Koramaz Valley, which are the subject of the study, are examined in detail and the differences between the columbarium tombs and the dovecotes are clearly revealed.

Cooperative diversity has spatial diversity effects on wireless communication systems to combat fading effects by using idle antennas as relays which are already located in the system. OFDM based cooperative communication is widely used in wireless communication systems and promises high data rate. However, OFDM has high PAPR problem. The high PAPR causes the interference and performance loss. Carrier interferometry codes boost overall performance of OFDM communication systems and decrease the level of PAPR. FFT can be used to realize carrier interferometry with no performance degradation. In this paper PAPR performance of the carrier interferometry OFDM by wavelet transform is analysed in a cooperative relay network. The results show that, the system which is a novel design of CI-OFDM has obviously better performance than traditional systems in terms of both BER and PAPR with the assist of wavelet transform.