A smart LED lighting system is designed and implemented using a multi-sensor module and Bluetooth Low Energy (LE) technology. In order to monitor the environmental information such as ambient light intensity, temperature, and/or activity of human or other objects, a multi-sensor module including an ambient light sensor, temperature sensor, and motion sensor is combined to a microcontroller. By collecting environmental information, the LED lighting system can be controlled automatically. Through the Bluetooth LE technology, a user can monitor the environmental information on a smartphone and/or control the LED lighting system manually. Two features, multi-sensor module and Bluetooth LE, let the LED lighting system be more intelligent, energy efficient, and convenient lighting system.

ABSTRACT In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual‐hop relaying where a relay with multiple‐antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade‐off of performance and complexity by comparing the average number of active antennas, path estimations, and signal‐to‐noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

ABSTRACT In this paper, we consider the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of perfect feedback channels. We quantify the performance of two joint AMDC schemes in the presence of feedback error, in terms of the average spectral efficiency, the average number of combined paths, and the average bit error rate. The benefit of feedback error compensation with adaptive combining is also quantified. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining. Copyright © 2011 John Wiley & Sons, Ltd.

Two-way relaying is the one of the solutions to mitigate the loss in spectral efficiency due to the half-duplex transmission in the multi-hop communication. In this paper we propose a simple two-way relaying scheme for the two-hop two-user multiple input multiple output (MIMO) system. In this system, a base station and a relay station (RS), both equipped with two antennas, form a point-to-point MIMO channel while RS and two single-antenna mobile users form a point-to-multipoint multiuser MIMO channel. Based on the proposed scheme, we also propose optimal power allocation algorithm at RS. Through the numerical examples, we show that our proposed scheme achieves significant sum rate gain compared to the one-way relaying scheme and its performance gain increases as the distance between RS and both users becomes closer.

In this paper, we propose an adaptive beam deactivation scheme for the coordinated multi-cell multiuser multiple-input multiple-output (MU-MIMO) downlink system with limited feedback. In the proposed scheme, each user feeds back the indices of a desired beam and multiple undesired beams from its codebook and some channel quality indicators to its base station (BS). Based on the feedback information and the proposed transmitting user set selection algorithm, the coordinating BSs select one user for each BS to serve. Through the numerical example, we show that the proposed scheme achieves comparable sum rate gain compared to the conventional zeroforcing based coordinated multi-cell system with reduced feedback load.

In this paper, we consider the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of perfect feedback channels. In order to compensate for the performance degradation due to feedback error, we propose the path adjustment algorithm for diversity combining. We quantify the performance of the joint AMDC scheme in the presence of feedback error, in terms of the average spectral efficiency, the average number of combined paths, and the average bit error rate. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining.

In this paper, we propose several relay selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes are based on dual-hop relaying with multiple relays. We analyze the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigate the tradeoff of performance and complexity among proposed schemes by evaluating the average number of active relays, path estimations, and signal- to-noise ratio comparisons. Our proposed schemes and analysis are also applicable to single relay systems with multiple antennas.

We propose and analyze in this letter new finger management techniques which are applicable for RAKE receivers operating in the soft handover region. These schemes employ "distributed" types of generalized selection combining (GSC) and minimum selection GSC schemes in order to minimize the impact of sudden connection loss of one of the active base stations. By accurately quantifying the average error rate, we show through numerical examples that our newly proposed distributed schemes offer a clear advantage in comparison with their conventional counterparts.

This letter investigates the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of error-free feedback channels. We also propose to utilize adaptive diversity to compensate for the performance degradation due to feedback error. We accurately quantify the performance of the joint AMDC scheme in the presence of feedback error, in terms of the average number of combined paths, the average spectral efficiency, and the average bit error rate. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining. It is observed that the proposed compensation strategy can offer considerable error performance improvement with little loss in processing power and spectral efficiency in comparison with the no compensation case.

We propose and analyze new finger assignment schemes which are applicable for RAKE reception in the soft handover region. These schemes rely on variants of the conventional generalized selection combining (GSC) and the minimum selection GSC schemes in order to choose an acceptable base station and its corresponding paths. Relying on some recently derived results on order statistics, we investigate the average error rate performance as well as the average number of estimated and combined paths of the proposed schemes over independent and identically distributed Rayleigh fading channels. The mathematical formalism is illustrated with few selected numerical results that show the tradeoff between performance and processing power consumption.

This paper investigates the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of error-free feedback channels. We also propose to utilize adaptive diversity to compensate for the performance degradation due to feedback error. We accurately quantify the performance of the joint AMDC scheme in the presence of feedback error, in terms of the average number of combined paths, the average spectral efficiency, and the average bit error rate. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining. It is observed that the proposed compensation strategy can offer considerable error performance improvement with little loss in processing power and spectral efficiency in comparison with the no compensation case.

We propose and analyze in this paper a new finger assignment technique that is applicable for RAKE receivers when they operate in the soft handover (SHO) region. This scheme employs a new version of generalized selection combining (GSC). More specifically, in the SHO region, the receiver uses by default only the strongest paths from the serving base station (BS) and only when the combined signal-to-noise ratio (SNR) falls below a certain pre-determined threshold, the receiver uses more resolvable paths from the target BS to improve the performance. Hence, relying on some recent results on order statistics we attack the statistics of two correlated GSC stages and provide the approximate but accurate closed-form expressions for the statistics of the output SNR. By investigating the tradeoff among the error performance, the path estimation load, and the SHO overhead, we show through numerical examples that the new scheme offers commensurate performance in comparison with more complicated GSC-based diversity systems while requiring a smaller estimation load and SHO overhead.

We propose and analyze new finger assignment techniques that are applicable for RAKE receivers in the soft handover (SHO) region. Specifically, extending the results for the case of two-base station (BS), we consider the multi-BS situation, attack the statistics of several correlated generalized selection combining (GSC) stages, and provide closed-form expressions for the statistics of the output signal-to-noise ratio (SNR). By investigating the tradeoff among the error performance, the average number of required path estimations/comparisons, and the SHO overhead, we show through numerical examples that the new schemes offer commensurate performance in comparison with more complicated GSC-based diversity systems while requiring a smaller estimation load and SHO overhead.

We propose and analyze a new finger replacement technique that is applicable for RAKE receivers in the soft handover (SHO) region. More specifically, the receiver uses in the SHO region by default the strongest paths from the serving base station (BS) and only when the combined signal-to-noise ratio falls below a certain pre-determined threshold, the receiver uses more resolvable paths from the target BS to improve the performance. Instead of changing the configuration for all fingers, the receiver just compares the sum of the weakest paths out of the currently connected paths from the serving BS with the sum of the strongest paths from the target BS and selects the better group. Using accurate statistical analysis, we investigate in this letter the tradeoff between error performance, average number of required path comparisons, and SHO overhead offered by this newly proposed scheme.

We propose and analyze new finger assignment schemes which are applicable for RAKE reception in the soft handover region. These schemes rely on variants of the conventional generalized selection combining (GSC) and the minimum selection GSC schemes in order to choose an acceptable base station and its corresponding paths. Relying on some recently derived results on order statistics, we investigate the average error rate performance as well as the average number of estimated and combined paths of the proposed schemes over independent and identically distributed Rayleigh fading channels. The mathematical formalism is illustrated with few selected numerical results that show the tradeoff between performance and processing power consumption.

We propose and analyze in this paper new linger management techniques which are applicable for RAKE receivers operating in the soft handover region. These schemes employ "distributed" types of generalized selection combining (GSC) and minimum selection GSC schemes in order to minimize the impact of sudden connection loss of one of the active base stations. By accurately quantifying the average error rate, we show through numerical examples that our newly proposed distributed schemes offer a clear advantage in comparison with their conventional counterparts.

We propose and analyze new finger replacement techniques for RAKE reception in the soft handover (SHO) region with multiple base stations. The proposed schemes are basically based on the block comparison among groups of resolvable paths and lead to the reduction of complexity while offering commensurate performance in comparison with previously proposed schemes. Relying on the newly derived analytical expressions, we investigate not only the complexity in terms of the average number of required path estimations/comparisons and the SHO overhead but also the error performance of the proposed scheme over independent and identically distributed fading channels.

The authors propose and analyze new finger assignment techniques that are applicable for rake receivers in the soft handover (SHO) region. More specifically, in the SHO region, the receiver uses by default only the strongest paths from the serving base station (BS) and only when the combined signal-to-noise ratio (SNR) falls below a certain pre-determined threshold, the receiver uses more resolvable paths from the target BSs to improve the performance. Relying on the previous results for the case of two-BS case, the authors consider the multi-BS situation by attacking the statistics of several correlated generalized selection combining (GSC) stages and provide closed-form expressions for the statistics of the output SNR. By investigating the tradeoff among the error performance, the path estimation load, and the SHO overhead, the authors show through numerical examples that the new schemes offer commensurate performance in comparison with more complicated GSC-based diversity systems while requiring a smaller estimation load and SHO overhead.

We propose a new switched transmit diversity technique in MIMO systems with an application to Alamouti's space time block coding. The proposed scheme is basically a closed loop system where the feedback bits are sent back to the transmitter to indicate the channel quality. Various switching strategies, depending on the size of feedback bits, are considered and optimized to compare the trade-off between the link performance and the number of antennas or feedback information. From our analytical and numerical results, we show that there is a considerable benefit in terms of the performance and practical use.