8,500 research outputs found

    UTHM water quality classification based on sub index

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    River or stream at their source is unpolluted, but as water flow downstream, the river or lake is receiving point and non-point pollutant source. Ammoniacal nitrogen (NH3- N) and suspended solids (SS) strongly influences the dynamics of the dissolved oxygen in the water. Studies on monitoring this parameter were conducted for a river or lake but limited to the small man-made lake. This study is initiate to determine the changes in water quality of UTHM watershed as the water flows from upstream to downstream. The monitoring of NH3-N and TSS were monitored at two sampling schemes, 1) at the two-week interval and, 2) at a daily basis followed by the determination of the water quality sub-index particularly SIAN and SISS. The results showed that the two lakes in UTHM watershed were classified as polluted. In conclusion, the remedial action should be implemented to improve the water quality to meet the requirements at least to meet the recreational purpose

    Adaptive antennas at the mobile and base stations in an OFDM/TDMA system

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    In recent years, several smart antenna systems have been proposed and demonstrated at the base station (BS) of wire-less communications systems, and these have shown that significant system performance improvement is possible. In this paper, we consider the use of adaptive antennas at the BS and mobile stations (MS), operating jointly, in combination with orthogonal frequency-division multiplexing. The advantages of the proposed system includes reductions in average error probability and increases in capacity compared to conventional systems. Multiuser access, in space, time, and through subcarriers, is also possible and expressions for the exact joint optimal antenna weights at the BS and MS under cochannel interference conditions for fading channels are derived. To demonstrate the potential of our proposed system, analytical along with Monte Carlo simulation results are provided

    Range and throughput enhancement of wireless local area networks using smart sectorised antennas

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    Flexible dual-diversity wearable wireless node integrated on a dual-polarised textile patch antenna

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    A new textile wearable wireless node, for operation in the 2.45 GHz industrial, scientific and medical (ISM) band, is proposed. It consists of a dual-polarised textile patch antenna with integrated microcontroller, sensor, memory and transceiver with receive diversity. Integrated into a garment, the flexible unit may serve for fall detection, as well as for patient or rescue-worker monitoring. Fragile and lossy interconnections are eliminated. They are replaced by very short radiofrequency signal paths in the antenna feed plane, reducing electromagnetic compatibility and signal integrity problems. The compact and flexible module combines sensing and wireless channel monitoring functionality with reliable and energy-efficient off-body wireless communication capability, by fully exploiting dual polarisation diversity. By integrating a battery, a fully autonomous and flexible system is obtained. This novel textile wireless node was validated, both in flat and bent state, in the anechoic chamber, assessing the characteristics of the integrated system in free-space conditions. Moreover, its performance was verified in various real-world conditions, integrated into a firefighter garment, and used as an autonomous body-centric measurement device

    Performance of the Smart Antenna Aided Generalized Multicarrier DS-CDMA Downlink using both Time-Domain Spreading and Steered Space-Time Spreading

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    In this contribution a generalized MC DS-CDMA system invoking smart antennas for improving the achievable performance in the downlink of the system is studied, which is capable of minimizing the downlink interference inflicted upon co-channel mobiles, while achieving frequency, time and spatial diversity. In the MC DS-CDMA system considered the transmitter employs multiple antenna arrays and each of the antenna arrays consists of several antenna elements. More specifically, the space-time transmitter processing scheme considered is based on the principles of Steered Space-Time Spreading (SSTS). Furthermore, the generalized MC DS-CDMA system employs time and frequency (TF)-domain spreading, where a user-grouping technique is employed for reducing the effects of multiuser interference

    Modeling of wide-band MIMO radio channels based on NLoS indoor measurements

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    Coherent and Differential Downlink Space-Time Steering Aided Generalised Multicarrier DS-CDMA

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    This paper presents a generalised MultiCarrier Direct Sequence Code Division Multiple Access (MC DS-CDMA) system invoking smart antennas for improving the achievable performance in the downlink. In this contribution, the MC DSCDMA transmitter employs an Antenna Array (AA) and Steered Space-Time Spreading (SSTS). Furthermore, the proposed system employs both Time and Frequency (TF) domain spreading for extending the capacity of the system, which is combined with a user-grouping technique for reducing the effects of Multi-User Interference (MUI). Moreover, to eliminate the high complexity Multiple Input Multiple Output (MIMO) channel estimation required for coherent detection, we also propose a Differential SSTS (DSSTS) scheme. More explicitly, for coherent SSTS detection MVNr number of channel estimates have to be generated, where M is the number of transmit AAs, V is the number of subcarriers and Nr is the number of receive antennas. This is a challenging task, which renders the low-complexity DSSTS scheme attractive. Index Terms—MIMO, MC DS-CDMA, beamforming, spacetime spreading, differential space-time spreading
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