PAPR reduction technique for LTE OFDMA systems

Long term evolution (LTE) is the final step toward the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile networks. LTE uses orthogonal frequency division multiple access (OFDMA) for the downlink transmission and single carrier-frequency division multiple access (SC-FDMA) for uplink. OFDMA meets the 4G requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates. However, the potentially large peak-to-average power ratio (PAPR) of the transmitting signals has limited its application. This high PAPR causes interference when the OFDM signals are passed through an amplifier which does not have enough linear range. In this article, we investigate a clipping based PAPR reduction method for LTE OFDMA systems. Simulation results show that the clipping method is reduced PAPR significantly which decreases as the number of clip and filtering level is increased. As a results, increase the mean transmit power, and improve the power amplifier efficiency. This comes at the outlay of complexity, efficiency as well as cost.

Peak to average power ratio analysis for LTE systems

The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SCFDMA) scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. SCFDMA uses DFT spreading prior to OFDMA modulation to map the signal from each user to a subset of the available subcarriers i.e., single carrier modulation. The efficiency of a power amplifier is determined by the peak to average power ratio (PAPR) of the modulated signal. In this paper, we analyze the PAPR in 3GPP LTE systems using root raised cosine based filter. Simulation results show that the SCFDMA subcarrier mapping has a significantly lower PAPR compared to OFDMA. Also comparing the three forms of SCFDMA subcarrier mapping, results show that interleave FDMA (IFDMA) subcarrier mapping with proposed root raised cosine filter reduced PAPR significantly than localized FDMA (LFDMA) and distributed (DFDMA) mapping. This improves its radio frequency (RF) power amplifier efficiency and also the mean power output from a battery driven mobile terminal.

Xploring txtuality & txtually transmitd dis-Ez : exploring textuality & textually transmitted dis-ease

In studyn th sociolog of transl8n, ther is logic n atemptin 2 stay az tru 2 form az possbl n reportin on studies, 4 wat is known is n de performanc of reportin, furthr transl8ns ocur. + additionl & praps unesary distortns ocur wen d resrch is bEing disemN8d. Taking a performativ turn, research disein8n attnds 2 > than th aesthetic. N nvestig8ng how young ppl bcom positind n thR preferences 4 textn ther iz positnin dat trivializs, pathologizs & marginalizs. N only attendin 2 a sanitizd voice, 1 made 2 fit th acadimc audiens, transl8d in2 d discours of th0s situa8d n d mainstrem, proceses of colonz8n & opresn r perpetu8d. N givng academic credens 2 particla voices & not othrs, conventns of academia suport a domiNt discours: "to b takn serious dont stay az u r". This papr ther4 focuss on a partclr part of reserch, the collatral damge of reserch dissemn8n that restrcts & altrs voice. 2 redres violenc gainst such voices, a performativ turn is takn.