This paper proposes out-of-band emission reduction schemes for IEEE 802.11af based Wireless Local Area Network (WLAN) systems operating in TV White Spaces (TVWS). IEEE 802.11af adopts Orthogonal Frequency Division Multiplexing (OFDM) to exploit the TVWS spectrum effectively. The combination of the OFDM and TVWS may be able to solve the problem of frequency depletion. However the TVWS transmitter must satisfy a strict transmission spectrum mask and reduce out-of-band emission to protect the primary users. The digital convolution filter is one way of reducing the out-of-band emission. Unfortunately, implementing a strict mask needs a large number of filter taps, which causes high implementation complexity. Time-domain windowing is another effective approach. This scheme reduces out-of-band emission with low complexity but at the price of shortening the effective guard interval. This paper proposes a mechanism that jointly uses these two schemes for out-of-band emission reduction. Moreover, the appropriate windowing duration design is proposed in terms of both the out-of-band emission suppression and throughput performance for all mandatory mode of IEEE 802.11af system. The proposed time-domain windowing design reduces the number of multiplier by 96.5%.

Demand for wireless communication is increasing significantly, but the frequency resources available for wireless communication are quite limited. Currently, various countries are prompting the use of TV white spaces (TVWS). IEEE 802.11 Working Group (WG) has started a Task Group (TG), namely IEEE 802.11af, to develop an international standard for Wireless local Area Networks (WLANs) in TVWS. In order to increase maximum throughput, a channel aggregation mechanism is introduced in the draft standard. In Japan, ISDB-T based area-one-segment broadcasting system (Area-1seg) which is a digital TV broadcast service in limited areas has been permitted to offer actual TVWS services since April 2012. The operation of the IEEE 802.11af system shall not jeopardize the Area-1seg system due to the common operating frequency band. If the Area-1seg partially overlaps with the IEEE 802.11af in some frequency, the IEEE 802.11af cannot use the channel aggregation mechanism due to a lack of channels. As a result, the throughput of the IEEE 802.11af deteriorates. In this paper, the physical layer of IEEE 802.11af D4.0 is introduced briefly, and a partial subcarrier system for IEEE 802.11af is proposed to efficiently use the TVWS spectrum. The IEEE 802.11af co-exist with the Area-1seg by using null subcarriers. Computer simulation shows up to around 70% throughput gain is achieved with the proposed mechanism.

This paper investigates the communication range and interference range of millimeter-wave wireless personal area networks (WPAN) based on realistic system design. Firstly, the effective communication range of the millimeter-wave networks are calculated based on realistic physical (PHY) layer design and 60 GHz channel obtained from actual measurements. Secondly, an interference model is developed to facilitate the analysis of the impact of interferer-to-victim range on the victim link performance. It is found that system with BPSK modulation is able to support use cases with higher number of portable devices within a 3 m range, while system with 16QAM modulation is more suitable for fixed high speed data streaming devices within a shorter range of 1 m. Also, the interferer-to-victim range that causes no interference in all conditions is found to be approximately 40 m, while a 25 m range causes a typical bit error rate (BER) degradation of 1-digit (e.g. BER = 10-6 to 10-5).

This paper proposes a prioritized aggregation method that supports compressed video transmission on millimeter wave wireless personal area network (mmWave WPAN) systems. Frame aggregation is an effective means to improve system efficiency and throughput for wide band systems such as mmWave WPAN. It is required by the applications that the mmWave WPAN systems should provide Gbps or multiGbps transmission capability. The proposed scheme targets not only transmission efficiency but also support of compressed video transmission which currently is very popular. The proposal combines MAC layer aggregation with PHY layer skew modulation to facilitate the video transmission in a way that more important data is better protected. Simulation results show that the average peak signal to noise ratio (PSNR) performance is improved by 5 dB compared to conventional method, while the Gbps transmission requirement is fulfilled.

IEEE 802.15.3c has been standardized for wireless personal area networks (WPANs) to realize high-speed wireless communications with 1 Gbps throughput. In this paper we introduce a 802.15.3c WPAN prototype. The introduced 802.15.3c WPAN prototype applies the enhanced MAC functions of data separation on hybrid multiple access, long frame size, aggregation, block acknowledgment, and timing operation, which can realize Gbps throughput in IEEE 802.15.3c. Moreover, the experiment performance studies on the prototype show that around 1.6 Gbps throughput can be successfully achieved and video streaming applications can be accommodated. Also, our studies provide the useful information of MAC capacity for developing the 802.15.3c devices.

In this paper, throughput and error performance analysis is conducted on the proposed space-time resource management (STRM) scheme to realize a multi-Gbps millimeter-wave wireless personal area network (WPAN) system. The proposed STRM allows multiple peer-to-peer communication links to occupy the same time-division-multiple-access (TDMA) time slot, in contrary to the conventional TDMA system that allocates only one time slot to one communication link. Theoretical analysis is performed to investigate the achievable system throughput in the presence of co-channel interference (CCI) generated by communication links co-sharing the same time slot. To increase accuracy, the analysis results are validated by Monte Carlo simulations. Firstly, it is found that the upper bound of the achievable throughput increases linearly with the number of communication links sharing the same time slot. However, optimum throughput exists corresponding to the CCI present in the system. Secondly, by manipulating a parameter that controls the allowable CCI in the network, the system throughput can be optimized. Lastly, it is also found that in a millimeter-wave band system, a victim system with transmitter-receiver separation of 1-meter can achieve bit error rate (BER) of 10-6 provided that the interferer is at least 6-meters away.

This paper presents the analysis on hidden node due to multiple transmission power level and its potential impact to system performance of White Space radio operating in the TV bands, a.k.a TV white space (TVWS). For this purpose, a generic interference model for determining the hidden node occurrence probability based on realistic physical (PHY) layer model is developed. Firstly, the generic hidden node interference model is constructed considering typical TVWS radio network deployment scenario. Emphasis is given on cases where the hidden node scenario involves multiple transmission power level. Secondly, the PHY layer design and channel propagation are modeled to analyze the realistic operating range of the TVWS radio. By combining the hidden node interference model and the PHY layer/propagation models, the realistic probability of hidden node occurrence is calculated. Finally, the performance degradation in the victim receiver due to interference generated by the potential hidden node is quantified. As a result, for urban environment, it is found that for networks consisting of devices with multiple transmit power level, the probability of hidden node occurrence is similar to that of networks consisting of devices with uni-transmit power level, provided that the interferer-victim separation distance in the former is 800 m farther apart. Furthermore, this number may increase to a maximum of 1.1 km in a suburban environment. Also, it is found that if the hidden node actually occurs, a co-channel interference (CCI) of -15 dB typically causes a degradation of 2 dB in the victim receiver.