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).

On Coexistence of Vehicular Overlay Network and H2H Terminals on PRACH in LTE

Vehicular ad hoc networks （VANETs） that use the IEEE 802.11p communication standard face a number of challenges, not least when it comes to safety messages on the VANET control channel （CCH） where short delay times and reliable delivery are of pri- mary importance. In this paper we propose a vehicular machine-to-machine （VM2M） overlay network that uses Long Term Evolu- tion （LTE） physical random access channel （PRACH） to emulate VANET CCH. The overlay network uses dedicated preambles to separate vehicular traffic from regular LTE traffic and a cartier sense multiple access with collision avoidance （CSMA-CA） layer similar to the one used in IEEE 802.15.4 to avoid the four step handshake and the overhead it incurs. The performance of the pro- posed overlay is evaluated under a wide range of PRACH parameters which conform to the scenarios with high vehicle velocities and large distances between roadside units （RSUs） that may be encountered in rural areas and on highways.

Evolution characteristics of seismic intensity in Tangshan seismic zone

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LTE系统中多类别业务的调度算法研究

本文针对目前算法处理多类别业务时低优先级业务带宽不足,影响整体服务质量(Quality of Service,QoS)的问题,提出用于多类别业务的新的调度算法,包括用于eNodeB的多类别业务调度算法和用于UE的多类别业务优先级调整算法。通过本文算法,能保证紧急要求的UE总是被优先调度,能够最大化MAC层吞吐量,同时能满足最小QoS约束,并进一步改善低优先级业务的资源不足的问题。实验表明本文算法能显著改善LTE上行链路性能。

Quality of experience based scheduling algorithm in LTE network with various traffics

Quality of experience （ QoE ） based scheduling algorithm of long term evalution （ LTE ） network with various traffics is studied. Utility functions are adopted to estimate mean opinion score （MOS） for different traffics and a new MOS metric called normalized MOS is defined. A scheduling algorithm based on normalized MOS and greedy algorithm is proposed, aiming at maximizing the entirety MOS level of the whole users in the cell. We compare the performance of the proposed algorithm with other typical scheduling algorithms and the simulation results show that the algorithm pro- posed outperform other ones in term of QoE and fairness.

Elite Opposition Based Metaheuristic Framework for Load Balancing in LTE Network

In present scenario of wireless communications,Long Term Evolution(LTE)based network technology is evolved and provides consistent data delivery with high speed andminimal delay through mobile devices.The traffic management and effective utilization of network resources are the key factors of LTE models.Moreover,there are some major issues in LTE that are to be considered are effective load scheduling and traffic management.Through LTE is a depraved technology,it is been suffering from these issues.On addressing that,this paper develops an Elite Opposition based Spider Monkey Optimization Framework for Efficient Load Balancing(SMO-ELB).In this model,load computation of each mobile node is done with Bounding Theory based Load derivations and optimal cell selection for seamless communication is processed with Spider Monkey Optimization Algorithm.The simulation results show that the proposed model provides better results than exiting works in terms of efficiency,packet delivery ratio,Call Dropping Ratio(CDR)and Call Blocking Ratio(CBR).

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.

ENERGY-SAVING SCHEDULING FOR LTE MULTICAST SERVICES

In the Long Term Evolution(LTE)downlink multicast scheduling,Base Station(BS)usually allocates transmit power equally among all Resource Blocks(RBs),it may cause the waste of transmit power.To avoid it,this paper put forward a new algorithm for LTE multicast downlink scheduling called the Energy-saving based Inter-group Proportional Fair(EIPF).The basic idea of EIPF is to calculate an appropriate transmitting power for each group according to its data rate respectively,and then follow the inter-group proportional fair principle to allocate RBs among multicast groups.The results of EIPF simulation show that the proposed algorithm not only can reduce the transmit power of BS effectively but also improve the utilization rate of energy.

TCP TRAFFIC PERFORMANCE IMPROVING IN LTE-A NETWORKS

This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems. Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained. However, those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks. In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed. The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell, as well as reducing radio resources in LTE-A macro cells.

Triple-Polarized Multi-User Mimo-Idma System under Correlated Fading Channel

A multiple-input multiple-output interleave division multiple access (MIMO-IDMA) system with Triple Polarized Division Multiplexing (TPDM) is presented in this paper. The present methodology replaces three independent linearly polarized antennas with a single triple polarized antenna at both the transmitter and receiver. The users in the communication link are accommodated and separated using a user-specific interleaver combined with low rate spreading sequence. To eliminate the effects of multi-stream interference (MSI), minimum mean square error (MMSE) algorithm based on successive interference cancellation (SIC) Multi-user detection (MUD) technique is employed at the receiver. Furthermore, log-maximum a posteriori probability (MAPP) decoding algorithm is implemented at the mobile stations (MSs) to overcome the effects of multi-user interference (MUI) effects. The paper also evaluates the effects of coded MIMO-IDMA in the downlink communication by adopting the Stanford University Interim (SUI) and Long-term Evolution (LTE)channel model specifications. In comparison with the traditional uncoded system, the present solution considering turbo coded triple-polarized MIMO-IDMA system with iterative decoding algorithm provides better bit error rate (BER) with reduced signal to noise ratio (SNR). The simulation results also show that though the SNR requirement is higher for the proposed technique compared to the conventional uni-polarized antenna based MIMO-IDMA system, it gives the advantages of achieving higher data rate with reduced cost and space requirements in the context of a downlink (DL).

Design of broadband class-F power amplifier for multiband LTE handsets applications

A broadband class-F power amplifier for multiband LTE handsets applications is developed across 2.3- 2.7 GHz. The power amplifier maintains constant fundamental impedance at the output matching circuit which is operating for broadband. The nearly zero of second harmonic impedance and nearly infinity of third harmonic impedance are found for highly efficient class-F PA. The harmonic control circuits are immersed into the broad- band output matching for fundamental frequency. For demonstration, the PA is implemented in InGaP/GaAs HBT process, and tested across the frequency range of 2.3-2.7 GHz using a long-term evolution signal. The presented PA delivers good performance of high efficiency and high linearity, which shows that the broadband class-F PA supports the multiband LTE handsets applications.

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.

A high linearity downconverter for SAW-less LTE receivers

This paper presents a high linearity downconverter implemented in a 0.18μm CMOS process for long term evolution（LTE） receivers without a surface acoustic wave（SAW） filter.The proposed downconverter is composed of a transconductance（Gm） stage,a passive mixer,a current buffer,a transimpedance（TIA） stage,and a DC-offset cancellation（DCOC） loop.The current buffer is utilized to provide very low load impedance for the passive mixer at high frequencies and reduce the output voltage swing induced by out-of-band blockers.This technique improves the input referred third-order intercept point（IIP3） and second-order intercept point（IIP2） of the down-converter by 4.5 dB and 11 dB,respectively.The measured results show that the proposed downconverter achieves a voltage conversion gain of 29.5 dB,double sideband noise figure of 12.7 dB,out-of-band IIP3 of 13 dBm and IIP2 of more than 62 dBm.

QoS-priority based load balancing algorithm for LTE systems with mixed users

Focusing on the load balancing problem among multi-cells in long term evolution （LTE） networks with mixed users, a new multi-objective optimization modeling strategy, which integrates the guaranteed bit rate （GBR） and the best effort （BE） users, was proposed. In consideration of quality of service （QoS） priorities of different users, a decomposition method was presented to solve the original model. Derivations such as applying Lagrange multiplier method, sub-optimal solutions for mixed users were deduced. Based on derived solutions, including resource allocation schemes, a practical multi-objective load balancing algorithm jointly dealing with mixed users was given. Simulation shows a significant improvement of GBR users＇ satisfaction level and BE users＇ throughput in LTE networks by using the proposed algorithm.

OpenMDSP:Extending OpenMP to Program Multi-Core DSPs

Multi-core digital signal processors （DSPs） are widely used in wireless telecommunication, core network transcoding, industrial control, and audio/video processing technologies, among others. In comparison with general-purpose multi-processors, multi-core DSPs normally have a more complex memory hierarchy, such as on-chip core-local memory and non-cache-coherent shared memory. As a result, efficient multi-core DSP applications are very difficult to write. The current approach used to program multi-core DSPs is based on proprietary vendor software development kits （SDKs）, which only provide low-level, non-portable primitives. While it is acceptable to write coarse-grained task-level parallel code with these SDKs, writing fine-grained data parallel code with SDKs is a very tedious and error-prone approach. We believe that it is desirable to possess a high-level and portable parallel programming model for multi-core DSPs. In this paper, we propose OpenMDSP, an extension of OpenMP designed for multi-core DSPs. The goal of OpenMDSP is to fill the gap between the OpenMP memory model and the memory hierarchy of multi-core DSPs. We propose three classes of directives in OpenMDSP, including 1） data placement directives that allow programmers to control the placement of global variables conveniently, 2） distributed array directives that divide a whole array into sections and promote the sections into core-local memory to improve performance, and 3） stream access directives that promote big arrays into core-local memory section by section during parallel loop processing while hiding the latency of data movement by the direct memory access （DMA） of a DSP. We implement the compiler and runtime system for OpenMDSP on PreeScale MSC8156. The benchmarking results show that seven of nine benchmarks achieve a speedup of more than a factor of 5 when using six threads.

GPP-Based Soft Base Station Designing and Optimization

It is generally acknowledged that mobile communication base stations are composed of hardware components such as Field Programming Gate Array （FPGA）, Digital Signal Processor （DSP）, which promise reliable and fluent services for the mobile users. However, with the increasing demand for energy-efficiency, approaches of low power-consumption and high-flexibility are needed urgently. In this circumstance, General Purpose Processor （GPP） attracts people＇s attention for its low-cost and flexibility. Benefited from the development of modern GPP in multi-core, Single Instruction Multiple Data （SIMD） instructions, larger cache, etc., GPPs are capable of performing high-density digital processing. In this paper, we compare several software-defined radio （SDR） prototypes and propose the general architecture of GPP-based soft base stations. Then, the schematic design of resource allocation and algorithm optimization in soft base station implementation are studied. As an application example, a prototype of GPP-based soft base station referring to the 3rd Generation Partnership Project （3GPP） Long Term Evolution （LTE） is realized and evaluated. To the best of our knowledge, it is the first Soft-LTE prototype ever reported. In the end, we evaluate the timing performance of the LTE soft base station and a packet loss ratio of less than 0.003 is obtained.

Frequency synchronization for TD-LTE-A downlink receiver

A high accuracy frequency synchronization method is proposed for the 3rd generation partnership project （3GPP） long term evolution advanced （LTE-A） downlink receiver in time division duplexing （TDD） mode. In general, cyclic prefix （CP） correlation based fractional frequency offset （FFO） estimation method and primary synchronization signal （PSS） differential correlation based integer frequency offset （IFO） estimation method are applied for LTE-A frequency synchronization. However, the polarity of CP based FFO estimation result may get reversed when system FFO is closer to the edge of frequency estimation range on account of noise interference; PSS based IFO estimation has performance degradation in low signal noise ratio （SNR）. We propose polarity detection aided CP based FFO estimation and frequency domain enhanced differential correlation based IFO estimation to obtain higher accuracy of frequency synchronization. Computer simulation shows that the proposed method greatly outperforms the conventional methods, especially in low SNR scenario.

Doppler ambiguity analysis and suppression for LTE-based passive bistatic radars

In this study,we provide a detailed analysis of the frequency division duplex long term evolution downlink(FDD LTE DL)signal for passive bistatic radars that use the signal as an illuminator of opportunity.In particular,we analyze the crossambiguity function and illustrate its undesired deterministic peaks in the Doppler dimension due to the specific structure of the FDD LTE DL signal.A new adaptive mismatched filtering method is proposed for pre-processing the original reference signal to suppress these undesired deterministic peaks in the range-Doppler processing.The effectiveness of our proposed method is demonstrated via simulations following robustness analysis,showing that all undesired peaks are suppressed below-40 dB,with only 1.7 dB reduction in the main peak.