Array (Smart) Antennas Improve GSM Performance

As wireless data applications over cellular networks become more widespread, the pressure to increase capacity will become even more intense. Capacity in the 800 and 900 MHz bands, where bandwidth is restricted, is already becoming a limiting factor. This paper attempts to address how the application of smart antenna systems has brought about improvements in call quality and increased capacity through reduced Interference in Mobile Communication. The smart antenna may be in a variety of ways to improve the performance of a communications system. Perhaps most importantly is its capability to cancel co-channel interference. It helps in improving the system performance by increasing the channel capacity, spectrum efficiency, extending range coverage, speech quality, enabling tighter reuse of frequencies within a cellular network and economically, feasible increased signal gain, greater, reduced multipath reflection. It has been argued that Smart antennas and the Algorithms to control them are vital to a high-capacity communication system development.

An externally perceivable smart leaky-wave antenna based on spoof surface plasmon polaritons

Smart antennas have received great attention for their potentials to enable communication and perception functions at the same time.However,realizing the function synthesis remains an open challenge,and most existing system solutions are limited to narrow operating bands and high complexity and cost.Here,we propose an externally perceivable leakywave antenna(LWA)based on spoof surface plasmon polaritons(SSPPs),which can realize adaptive real-time switching between the“radiating”and“non-radiating”states and beam tracking at different frequencies.With the assistance of computer vision,the smart SSPP-LWA is able to detect the external target user or jammer,and intelligently track the target by self-adjusting the operating frequency.The proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna,and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating frequency.On the other hand,it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real time.In addition,the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems.

A Genetic Algorithm-Based Smart Antenna Technique for Anti-Collision of Multiple SAW ID-Tags

In the radio frequency identification (RFID) system based on surface acoustic wave (SAW) technique, some tags often locate in the field of a transceiver at the same time. These tags produce simultaneous echo signals which "collide" when they arrive back at the transceiver, which leads to difficult identification. In this paper, smart antenna technique is presented to implement anti-collision in SAW RFID system. The direction of arrivals (DOAs) are used to denote the locations of tags, and genetic algorithm (GA) is suggested to find the optimal estimates of the DOAs in complex multimodal search spaces. Once the DOAs are obtained, the array weights are formed and the signals of tags are recovered to implement decoding. The experimental results show that the GA-based smart antenna technique works well in some occasions.

An Inductor Model for Analyzing the Performance of Printed Meander Line Antennas in Smart Structures

Meander line antenna has been considered desirable on flight vehicles to reduce drag and minimize aerodynamic disturbance;however, the antenna design and performance analysis have made mostly by trial-and-error. An inductor model by simulating the meander line sections as electrical inductors and the interconnecting radiation elements as a quasi-monopole antenna is developed to analyze the antenna performance. Experimental verifications of the printed meander line antennas embedded in composite laminated substrates show that the inductor model is effective to design and analyze. Of the 4 antennas tested, the discrepancy of resonant frequency in simulation and experiment is within 4.6%.

TRANSFORM DOMAIN SMART ANTENNAS ALGORITHM FOR MAI SUPPRESSION

Multiple Access Interference(MAI) is the major factor that degrades the performance of a CDMA system. In this paper, a novel transform domain algorithm combined with parameter estimation for MAI suppression is proposed. Compared with the method that combines an adaptive array antenna with parameter estimation for interference suppression, it converges faster with the same Bit Error Rate(BER) performance.

INVESTIGATION OF UPLINK RADIO RESOURCE MANAGEMENT SCHEMES FOR MULTI-SERVICES IN TDD-CDMA SYSTEMS EMPLOYING SMART ANTENNAS

In this paper, a theoretical analysis of Time Division Duplex-Code Division Multiple Access (TDD-CDMA) uplink capacity constraint is presented when employing the smart antenna techniques. The evaluation formulations of capacity and load for multi-services are proposed. In order to maximize the throughput, the objective of optimization is proposed, and an advanced uplink resource management algo-rithm is developed. The proposed algorithm based on the least interference admission control scheme focuses on the maximum throughput for the circuit switched multi-services. The simulation results show that the pro-posed strategy has a significant improvement in throughput when the optimum admission control threshold is set.

QTDMAC:MAC protocol for QoS support in MANET using smart antennas

Unlike directional antennas, smart antennas offer MANET (Mobile Ad hoc Net works) potential increases in their achievable throughput and capacity. Based on the development of smart antenna technology, we studied the MAC protocol for QoS support was studied, which becomes the hot issue in multimedia services. The protocol divides the channel into the data channel and the control channel, node sends forecast guarantee to compete the channel. And after completing the RTS / CTS handshake appointment, node is reserved for data transmission. Node can send Busy Tones to prevent the problem of the deafness nodes and hidden terminal. At last if the direct link between the sender and receiver has low quality and low rate, data packets may be delivered faster through a relay node. Through the analytical results, QTDMAC with the protocol IEEE802.1 and DMAC were compared. The QTDMAC protocol is proved the superiority in throughput and the real-time delay business.

Design Aspects of CMOS Compatible On-Chip Antenna for Applications of Contact-Less Smart Card

Design aspects of CMOS compatible on-chip antenna for applications of contact-less smart card are discussed.An on-chip antenna model is established and a design method is demonstrated.Experimental results show that system-on-chip integrating power reception together with other electronic functions of smart card applications is feasible.In a 6×10 -4T magnetic field of 22.5MHz,an on-chip power of 1.225mW for a 10kΩ load is obtained using a 4mm2 on-chip antenna.

MI-NLMS adaptive beamforming algorithm for smart antenna system applications

A Matrix Inversion Normalized Least Mean Square (MI-NLMS) adaptive beamforming algorithm was developed for smart antenna application. The MI-NLMS which combined the individual good aspects of Sample Matrix Inversion (SMI) and the Normalized Least Mean Square (NLMS) algorithms is described. Simulation results showed that the less complexity MI-NLMS yields 15 dB improvements in interference suppression and 5 dB gain enhancement over LMS algorithm, converges from the initial iteration and achieves 24% BER improvements at cochannel interference equal to 5. For the case of 4-element uniform linear array antenna, MI-NLMS achieved 76% BER reduction over LMS algorithm.

A MAC PROTOCOL TO SUPPORT HYBRID ANTENNAS IN A WIRELESS LAN

Hybrid Distributed Coordination Function (HDCF),a modified medium access control pro-tocol of IEEE 802.11 standard,is proposed in this paper to support both smart adaptive array anten-nas and normal omni-directional antennas simultaneously in one wireless LAN. Omni-directional an-tennas follow the standard Distributed Coordination Function (DCF) and smart antennas follow the Directional DCF (DDCF). The proposed DDCF is based on Hybrid Virtual Carrier Sense (HVCS) mechanism,which includes Omni-directional Request-To-Send/Clear-To-Send (ORTS/OCTS) hand-shake mechanism and directional data transmission. HDCF is compatible with DCF. When a node transmits in a directional beam,the other nodes can multiplex the physical channel. Hence,HDCF supports Space Division Multiple Access (SDMA). Simulation results show that HDCF can support hybrid antennas effectively and provide much higher network throughput and lower delay and jitter than DCF does.

Green Distributed Antenna Systems for Smart Communities: A Comprehensive Survey

Smart communities are an emerging communication means in which humans and smart devices will interact with each other and deliver ubiquitous services by exploiting social intelligence.Distributed antenna system(DAS),one of the key technologies to realize smart decisions in smart communities,can settle network smart coverage problem and improve system energy/spectrum efficiency significantly.Considering that energy consumption is an important element for community communications,in this paper,we survey the existing green DAS research for smart communities.In particular,our investigation covers antenna distribution,system capacity,spectrum efficiency,energy efficiency,and green access issues.Moreover,we analyze the existing application opportunities and challenges.This survey contributes to better understanding of the challenges and approaches for green DAS in existing smart community networks and further shed novel light on some future research directions.

Impact of WCDMA channel multiplexing on smart antenna systems

Smart antenna has been regarded as one promising technology to enhance the performance of CDMA mobile communication systems. However, when applied to 3G systems, the performance of traditional adaptive arrays may degrade due to code and time multiplexing in dedicated physical channels. A novel semiblind adaptive array approach is proposed to solve this problem. It overcomes the selfinterfering problem by introducing a quasidespreading technique for the control channel, and contains a timemultipexed structure to utilize both pilot symbols and unknown control symbols within the control channel. The blind part of the proposed approach is based on the competition of two parallel branches with different reference sequences. Simulation results show significant improvement can be achieved by the proposed approach in a fastfading WCDMA environment.

Performance of joint dual links dynamic power control and smart antenna for TDMA/TDD cellular mobile communications

Interference cancellation is made available by using smart antenna at cellular base stations. Well distributed cumulative probability of signal to interference plus noise power ratio appears to be vital for cellular mobile multimedia communications. A scenario of dual links dynamic power control combined to a solution of smart antenna is proposed to adjust the instant transmission power in terms of the disparity from the favorite range. Simulation results show that this method is quite effective to improve the cumulative distribution probability performance. Meanwhile, accompanying low power consumption is also obtained at both base stations and mobile stations.

Small MEMS smart antenna for software radio fuze

The signal transceiver of the software radio fuze depends on the front-end radio frequency（ RF） antenna. RF micro-electro-mechanical-system（ MEMS） smart antennas have the capability of flexible beam rapid scanning,multi-beam forming and so on,which can improve the ability of detecting,sensing and tracking multiple targets of the fuze. The small RF MEMS smart antenna consists of a 2 × 2 aperture coupled antenna array and six 1-bit MEMS phase shifters. Simulated results demonstrate that the antenna can complete beam steering angles of ± 30° in both X and Y plane at 17. 3 GHz. All components can be fabricated and monolithically integrated with MEMS technology which causes the system low cost and small volume. The RF MEMS smart antenna presents a good and important prospect for the development of the software radio fuze antenna.

An Optimized Design of Antenna Arrays for the Smart Antenna Systems

In recent years,there has been an increasing demand to improve cellular communication services in several aspects.The aspect that received the most attention is improving the quality of coverage through using smart antennas which consist of array antennas.this paper investigates the main characteristics and design of the three types of array antennas of the base station for better coverage through simulation(MATLAB)which provides field and strength patterns measured in polar and rectangular coordinates for a variety of conditions including broadsides,ordinary End-fire,and increasing directivity End-fire which is typically used in smart antennas.The method of analysis was applied to twenty experiments of process design to each antenna type separately,so sixty results were obtained from the radiation pattern indicating the parameters for each radiation pattern.Moreover,nineteen design experiments were described in this section.It is hoped that the results obtained from this study will help engineers solve coverage problems as well as improve the quality of cellular communication networks.

Review of Research Techniques to Improve System Performance of Smart Antenna

Today, the significance of the wireless communication is known all over the world. In order to achieve the better communication, many techniques and methods have been introduced. Among these techniques, smart/adaptive antennas are trending topic in the research domain. The smart antennas consist of various antennas arrays and have the ability to optimize the radia-tion and reception of the desired signals dynamically. Also, in order to avoid or mitigate the interferences, smart antennas can introduce nulls in the in-terferers direction by adaptive updating of the weights linked at every antenna element. The smart antennas can also enhance the quality of reception and reduce the dropped calls. This paper discusses the various survey topics related to smart antennas, Adaptive Beam Forming (ABF) algorithm etc. Also the various existing researches are discussed to know the research gap for future research scope.

Graphene-Based RFID Tag Antenna for Vehicular Smart Border Passings

Globalization has opened practically every country in the globe to tourism and commerce today.In every region,the volume of vehicles traveling through border crossings has increased significantly.Smartcards and radio frequency identification(RFID)have been proposed as a new method of identifying and authenticating passengers,products,and vehicles.However,the usage of smartcards and RFID tag cards for vehicular border crossings continues to suffer security and flexibility challenges.Providing a vehicle’s driver a smartcard or RFID tag card may result in theft,loss,counterfeit,imitation,or vehicle transmutation.RFID sticker tags would replace RFID tags as vehicle border passes to solve the mentioned problem.The RFID sticker tag adheres to the windscreen,side screen,dash,hood,or door of the vehicle,or any other acceptable location.Any damage or stripping from the installed location may cause data corruption and cannot be reused.Overall,these sticker tags will make the border crossingsmore secure and efficient.This article focuses on designing a rectangular-shaped RFID sticker tag antenna made of graphene sheets as a possible solution for smart border crossings.The proposed antenna is mathematically designed and analyzed with CST software to determine the optimum parameters.The design parameters are then used to create an antenna on a prepared graphene sheet.The performance results are carried out with CST software and a network analyzer.The designed RFID antenna stick on a car windscreen offers approximately 900 MHz bandwidth over the frequency range from 1.8 GHz to 2.7 GHz with an average gain of 1.23 dBi at the frequency to be used of 2.4 GHz microwave RFID band.The radiation is an omnidirectional pattern.The proposed graphene-sheet rectangular-shape monopole antenna is compact,low-cost,and bendable to fit into the windscreen of a car while retaining excellent wave propagation capabilities.These findings illustrate the suggested antenna’s potential as an RFID tag antenna in a vehicular smart border pass system.

NOVEL LSCM BEAM-FORMING ALGORITHM IN SMART ANTENNA MC-CDMA SYSTEM

A novel Least Squares Constant Modulus (LSCM) beam-forming algorithm in smart antenna Multi-Carrier Code Division Multiple Access (MC-CDMA) system is proposed in this paper. It adaptively beam-forms the multi-carrier antenna array signal using the LSCM Algorithm (LSCMA), and in the meantime, the beam-formed signals on every sub-carrier are combined by using Orthogonal Restore Combination (ORC), Equal Gain Combination (EGC) or Maximum Ratio Combination (MRC). Then the decision of the combined signals and the spread-code of the expected user are used to re-construct the signals on every sub-carrier. At last, the difference between the re-constructed signal and the output signal of the beam-former is used to con-trol the coefficients of the beam-former. The bit error probability of the proposed algorithm is analyzed. We simulated and compared it with the conventional LSCM beam-forming algorithm. Simulation results show that the proposed algorithm is superior to the latter in Bit Error Rate (BER).

AN ADAPTIVE MOVING TARGET TRACKING ALGORITHM FOR SMART ANTENNA SYSTEMS

In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival (DOA) tracking algorithms. On the other hand, although the DOA estimation methods based on the Maximum Likelihood (ML) principle have higher resolution than the beamforming and the subspace based methods, prohibitively heavy computation limits their practical applications. This letter first proposes a new suboptimal DOA estimation algorithm that combines the advantages of the lower complexity of subspace algorithm and the high accuracy of ML based algo- rithms, and then proposes a Kalman filtering based tracking algorithm to model the dynamic property of directional changes for mobile terminals in such a way that the association between the estimates made at different time points is maintained. At each stage during tracking process, the current suboptimal estimates of DOA are treated as measurements, predicted and updated via a Kalman state equation, hence adaptive tracking of moving MS can be carried out without the need to perform unduly heavy computations. Computer simulation results show that this proposed algorithm has better per- formance of DOA estimation and tracking of MS than the conventional ML or subspace based algo- rithms in terms of accuracy and robustness.