Complexity Effective Frequency and Sidelink Synchronization Algorithm for LTE Device-to-Device Communication Systems

Device-to-device(D2D)communication is considered as a major challenge in the long term evolution(LTE)network wherein devices directly communicate with each other.One of the key challenges in D2D sidelink is reliable and reduced-complexity synchronization.To address this issue,a computationally efficient sequential detection scheme for integer carrier frequency offset and sidelink identity is proposed in the LTE-D2D system.To perform the frequency offset detection without retrieving the sidelink identity,the conjugate relation between two primary sidelink synchronization sequences is exploited,which facilitates the detection tasks of frequency offset and sidelink identity to be decoupled.It is demonstrated from simulation results that the inherent property of the sidelink synchronization sequences is effectively used for joint detection of frequency offset and sidelink identity with significantly reduced complexity,compared to existing estimation schemes.

UEs Power Reduction Evolution with Adaptive Mechanism over LTE Wireless Networks

At present, the major drawback for mobile phones is the issue of power consumption. As one of the alternatives to decrease the power consumption of standard, power-hungry location-based services usually require the knowledge of how individual phone features consume power. A typical phone feature is that the applications related to multimedia streaming utilize more power while receiving, processing, and displaying the multimedia contents, thus contributing to the increased power consumption. There is a growing concern that current battery modules have limited capability in fulfilling the long-term energy need for the progress on the mobile phone because of increasing power consumption during multimedia streaming processes. Considering this, in this paper, we provide an offline meaning sleep-mode method to compute the minimum power consumption comparing with the power-on solution to save power by implementing energy rate adaptation(RA) mechanism based on mobile excess energy level purpose to save battery power use. Our simulation results show that our RA method preserves efficient power while achieving better throughput compared with the mechanism without rate adaptation(WRA).

LNA Design for Future S Band Satellite Navigation and 4G LTE Applications

A good design of LNA for S band satellite navigation receivers and 4G LTE wireless communication system has been implemented in this paper.Due to increased congestion in the present L band,the S Band frequency from 2483.5-2500 MHz has been allocated for the future satellite navigation systems.For this purpose ATF-34143 amplifier(pHEMT)having high electron mobility and fast switching response has been chosen due to its very low Noise Figure(NF).The amplifier has been designed having bandwidth of 0.8 GHz from 1.8-2.6 GHz.Because of the large bandwidth,the amplifier could serve many wireless communication applications including 4G LTE mobile communication at 2.1 GHz.The design was implemented using the micro strip technology offering extremely low noise figure of 0.312 dB and 0.377 dB for 2.1 GHz and 2.49 GHz respectively.The gain of the amplifier was low and found to be 10.281 dB and 9.175 dB.For the purpose of increasing the gain of an amplifier,the proposed LNA design was then optimized by using Wilkinson Power Divider(WPD).The Balanced LNA design using WPD offered very low noise figure of 0.422 dB and 0.532 dB respectively and the gain was considerably increased and was found to be 20.087 dB and 17.832 dB respectively against 2.1 GHz and 2.49 GHz.Simulations and measurements were taken in Agilent Advanced Design System(ADS)software.The suggested LNA can be used for a variety of wireless communications applications including the future S band satellite navigation systems.

Random access preamble design based on time pre-compensation for LTE-satellite system

Because of the integration of long term evolution （LTE） technology and mobile satellite communication systems, uplink access technology for LTE-based geo-stationary earth orbit （GEO） satellite has become a popular research topic for satellite system. In order to solve the problem of unreasonable design for physical random access channel （PRACH） signal structure and reduce the effect of time uncertainty, this paper proposes a novel random access preamble based on time pre-compensation （TPC） for LTE-Satellite （LTE-S） system. In this scheme, by applying the method of non-linear least squares, the user terminal （UT） can use and based on the transmission delay the receiving power to estimate the communication round trip delay （RTD） of the beam center and the satellite, RTD can be compensated before transmission. Therefore, the preamble length and duration can be reduced without related to the maximum of RTD. In order to verify the performance of the scheme, the MATLAB is used to build a test system. The simulation results show that the proposed preamble satisfies the requirements of LTE-S system, and the better performance than previous researches is obtained.