Punyawi Jamjareegulgarn

Detection of data symbol in a Massive MIMO systems for 5G wireless communication

The massive MIMO technique has played the most important role in 5G wireless communication. It is anticipated that the new techniques employed in massive MIMO will not only improve peak service data rates significantly, but also enhance capacity, coverage, low-latency, efficiency flexibility, compatibility and convergence, thus meeting the focusing demands imposed by optimal detection. This paper presents the optimal detection of data symbol in massive MIMO for 5G wireless communication. Based on the frequency non-selective fading MIMO channel, we consider three difference detectors for recovering the transmitted data symbols and evaluate their performance for Rayleigh fading and additive white Gaussian noise (AWGN). At the results, we show that the probability of error rate (PER) performance of the detectors are significantly discussed.

A new expression for computing topside scale height for satellite-based communications

It is well-known that the NeQuick 2 model provides analytical expressions showing a relationship between topside and bottomside ionospheres. Its bottomside thickness parameter (B2bot) is a key parameter for studying topside electron density profile (EDP) and topside parameters, and its topside scale height (Hsc) is also used to identify the topside electron density profile. The B2bot computed using ionogram-derived ionospheric parameters can be used to calculate the Hsc. Unfortunately, the Hsc computed by the original B2bot expression (Hsc_old) are significantly higher than the scale heights obtained from digisondes (Hm) and the diurnal variations of the Hsc_old are quite different from those of the Hm. Hence, a new expression of B2bot for computing the Hsc is suggested in this work relying on the available expressions of the NeQuick 2 model. Our results show that (1) the Hsc computed by the new expression of B2bot (Hsc_new) are comparable to the Hm and the diurnal variations in Hsc_new are the same trends as those in Hm; (2) all of the scale heights show diurnal variations with higher values during daytime than during nighttime and the secondary peaks can be found different local times relying on the locations; and (3) the peaks of scale height cause higher absolute differences between Hsc_new and Hm (D_SH).

Evaluating cooperative diversity-based WBAN by using STBC with pre-coding and relay selection

The main objective of this paper is to evaluate the network performance of a cooperative diversity-based wireless body area network (WBAN) by using (2,2) Alamoutis space-time block code (STBC) with pre-coding scheme (STBC-PC) and a relay selection procedure (RSP). The considered WBAN model is served for healthcare service in order to mitigate the undesired effects of WBAN due to high path loss and fading as well as to keep a low transmit power while meeting to the desired WBAN quality of services. In this paper, the pre-coding scheme is taken to be employed in conjunction with the STBC, since a single antenna of each wireless sensor node in healthcare service can be exploited possibly as well as the high gain can still be achieved without loss of transmission rate. A channel model CM3 B is considered for computing the actual path loss of each WBAN link and the network performance is evaluated in terms of bit error rate (BER). The simulation results confirm that at each BER value, SNRs of STBC-PC without direct link (line-of-sight or LOS) scheme are the lowest which is compared with direct link, receive diversity and MRC, and (2,2) Alamoutis STBC. BER values of DQPSK-based STBC-PC are higher than those of DBPSK-based STBC-PC. Moreover, although any WBAN sensor nodes are chosen as a relay or any type of modulations are employed in STBC-PC with LOS, all of BER values have surprisingly the same trend.

Vertical Assembled Sprayer for Supplying Water and Liquid Fertilizer

This paper proposes a vertical assembled sprayer for supplying water and liquid fertilizer. This proposed sprayer consists of both iron structure and hardware modules, including a microcon-troller, LCD, keypad, batteries, nozzles, and diaphragm pumps. The height of this proposed sprayer ranges from 1.5 to 4.5 meters so as to be adjusted by a user. The water quantity and the nozzle numbers can be specified by a user’s demand. Moreover, either manual or automatic operations can also be selected by a user. The experimental results have been shown that the average spraying times for using 1 - 4 nozzles are equal to 95.2 sec, 48.41 sec, 32.3 sec, and 24.5 sec, respectively. Moreover, the average spraying times from the experiments are close to the calculated spraying time of microcontroller where the errors are less than 2%.

Performance evaluation for cooperative diversity-based wireless body area network

This paper proposes cooperative diversity-based wireless body area network (WBAN) for healthcare service in order to mitigate the undesired effects of WBAN due to high path loss and fading as well as to keep a low transmit power while meeting to the desired WBAN quality of services, i.e., low outage probability and low bit error rate. In this paper, we consider all of the sensors which are placed on the human body, so CM3 B channel model is taken into account for computing the path loss of each WBAN link. Three well-known schemes for proactive relay selection have been addressed and applied in WBAN so as to compare the performance with the direct communication. The performance is evaluated in terms of outage probability (Pout) and bit error rate (BER). The simulation results confirm that Pout of cooperative diversity-based WBAN can be reduced higher 99.68% than that of direct communication at SNR of 0 dB and can be achieved below 4.5*10-4 at the low SNR of 0 - 6 dB. Moreover, BER of cooperative diversity-based WBAN can also be significantly decreased higher 99.89% than that of direct communication at all SNRs of 0 - 10 dB.