This study introduces a novel conservative modulation and coding scheme to minimize and stabilize the delay incurred during the process of electrocardiogram (ECG) transmission over a wireless medium, while maintaining the desired level of the ECG pattern quality required for improving the chance of its interpretation. A machine-type communication system is adopted for the delivery of ECG data to benefit from its inherent reliability, pervasiveness, security, and performance of 4G long-term evolution technologies with reduced cost and enhanced coverage. Extensive evaluations indicate that the proposed system provides a sufficient level of service for medical-grade instantaneous ECG monitoring even under significantly deteriorated channel conditions.

With rapid improvements in communication technologies and infrastructure, the Internet of Things (IoT) has become a promising sector within the global information and communication technology industry. Various fields are employing the concept of IoT for their traditional products and services for convenient use by consumers. In the construction industry, the majority of leading companies and organizations are using IoT technologies in a smart home environment. However, only few studies have focused on the user experience of IoT technologies in such an environment. Thus, the current study explores the key determinants of user acceptance of IoT technologies in a smart home environment, and investigates a research model integrated with five potential user factors and a technology acceptance model. The results of the collected data, which were investigated using a structural equation modeling method, show that three positive motivations, compatibility, connectedness, and control, and a negative hindrance, cost, are significant determinants of the technology acceptance behavior of users. The current study can serve as a foundation for future studies on improving IoT technologies in a smart home environment by considering the user experience.

Recent standardization efforts in the 3rd Generation Partnership Project (3GPP) have made the Long Term Evolution (LTE) system a very attractive radio access technology for various types of devices and applications. However, the system has not yet been optimized to support diverse traffic profiles. In this paper, we propose a group-based communication scheme to alleviate inefficiencies in the radio access network. The proposed scheme groups multiple connections triggered by different User Equipments (UEs). For the efficient grouping of the UEs, the location information of the Machine-Type Communication (MTC) devices is utilized to identify each group. A four-phase system model is presented to analyze each segment of the connection establishment procedure in the access network. We found that the random access procedure is the main variable factor for the communication delay, and we, therefore, carefully design the procedure with details. Simulations are conducted on our LTE testbeds, and the results show that the proposed scheme is very effective in ensuring the system performance of legacy services and in utilizing radio resources within a given delay bound.

Recent advances in communication and mobile computing have made it possible for cellular networks and digital broadcasting systems to converge on the basis of their common multimedia applications. We analyze the real-time characteristics of a cdma2000 1xEV-DO broadcast and multicast service (BCMCS) system, and propose a system architecture to provide seamless multimedia services. We found that jitter in the processing time of the Reed-Solomon decoder can lead to a discontinuity in multimedia streaming, and we therefore estimated the Reed-Solomon decoding time on a common mobile platform for a given bit error-rate or fading margin in the channel. Next we evaluated the jitter bound and the best cache size for real-time applications in BCMCS. This analysis allows us to suggest a system architecture based on the jitter-EDD model to ensure the continuity of real-time services for multimedia applications over a 3G cellular broadcast network, and to provide a better quality of service.

Abstract The error‐prone nature of the radio channel is the major challenge in servicing video streams over cdma2000 broadcast networks. The MAC protocol for broadcast and multicast services (BCMCS) in cdma2000 specifies forward error correction using Reed–Solomon coding, which is effective in recovering from bursts of errors. However, its performance degrades significantly when channel conditions are bad, a frequent occurrence at the edge of the coverage area, reducing the availability of high‐speed broadcasts. We propose an error recovery scheme and a scheduling algorithm based on the use of slots saved by changing to a Reed–Solomon code with a lower parity overhead. Within the fixed transmission budget thus created, corrupted packets are retransmitted in a priority order determined by a utility function that is derived from the map of the error control block at each mobile, and which also considers the number of mobiles that did not receive each lost packet. Simulation results show the effectiveness of the proposed scheme in improving the quality of high‐data‐rate MPEG‐4 video streams over a range of channel conditions. Copyright © 2007 John Wiley & Sons, Ltd.

Multimedia services over a CDMA2000 broadcast network face a challenge from the unreliable and error-prone nature of the radio channel. Reed–Solomon (RS) coding, integrated with the MAC protocol, is used to cope with this problem. However, performance analysis of RS coding under varying channel conditions shows that it is not always effective, especially for slow-moving nodes which experience relatively long error bursts. Therefore a more efficient scheme is proposed that uses a RS code with reduced parity overhead, and freeing bandwidth can be used flexibly for retransmission. The packets to be retransmitted are prioritised by a utility function derived from the map of the error control block at each mobile node and the number of mobile nodes that require the lost packet. Simulation results show that the gain of retransmission exceeds the loss incurred by reducing the parity, leading to an improvement in the playback quality of MPEG-4 video streams. As a result, service area for high-quality multimedia can be expanded.

The error-prone nature of the radio channel is the major challenge in servicing video streams over cdma2000 1/spl times/EV-DO broadcast networks. Forward error correction is commonly used when broadcasting a video stream over a lossy network: in BCMCS, the MAC protocol uses Reed-Solomon coding. We analyze the performance of Reed-Solomon error recovery with various parameter settings, and prove the correctness of our analysis through experiment. We also propose a hybrid-ARQ scheme to improve error recovery capacity in the BCMCS environment. Simulation results show a significant reduction in packet loss while quantitatively validating our approach.

We analyze the execution time of MAC-layer Reed-Solomon decoding in cdma2000 1xEV-DO broadcast and multicast services (BCMCS), using different cache sizes and a simulated air channel. MPEG-4 video is widely used for wireless multimedia services; however, it requires successive frames within a specific time interval, which can be missed by a MAC-layer Reed-Solomon decoder due to its computation time. We propose static and dynamic proactive Reed-Solomon bypass (PRSB) schemes to alleviate this problem in mobile nodes. Our first scheme bypasses the Reed-Solomon decoding process to satisfy the MPEG-4 time constraint statically, despite varying channel conditions. The second, dynamic scheme corrects errors in a best-effort manner within this same time constraint, leading to a further quality improvement. Extensive simulation results show a dramatic quality improvement in video quality

We analyze the performance of MAC-layer Reed-Solomon error recovery in the CDMA2000 1xEV-DO broadcast and multicast services (BCMCS) environment, with respect to the size of the error control block (ECB) and the air-channel condition, and establish the relationship between ECB size, error-recovery capacity and energy consumption. Real-time traffic, such as voice and video streaming, is very sensitive to delay, but can stand a certain level of packet loss. We therefore propose an energy-efficient size of the ECB to reduce the average energy consumption during error recovery while minimizing the reduction in service quality for real-time multimedia applications. Extensive simulation results suggest that a significant amount of energy can be saved with negligible performance degradation by selecting the appropriate ECB size for the bit error-rate of the forward traffic channel, instead of always choosing the largest possible ECB, with the sole aim of increasing error recovery performance

3GPP2 has recently introduced the Broadcast and Multicast Services (BCMCS) architecture for cdma2000 lxEV-DO wireless networks to enable service providers to broadcast multimedia content such as MPEG-4 video. For MAC-layer forward error correction the BCMCS scheme uses the Reed-Solomon (RS) decoding process, which consumes a considerable amount of energy on mobile phones. To address this problem, we first characterize the energy consumption of the decoder with respect to its components: the data decoder, error locator and erasure decoder. Based on this detailed energy characterization we propose an analytic energy model which takes account of different levels of bit error rate in the forward traffic channel. This model is then verified experimentally on an ARM microprocessor-based testbed. Our results will help design energy-efficient BCMCS systems for 3G cellular networks

We analyze the execution time of MAC-layer Reed-Solomon error recovery in cdma2000 1xEV-DO broadcast and multicast services (BCMCS), with respect to cache size and air channel condition. We observe that a deteriorating channel condition often causes an intolerable delay for real-time tasks because of the error recovery process, even when sufficient cache memory is available to increase CPU throughput. To overcome this problem, we propose proactive Reed-Solomon bypass (PRSB), which determines whether the Reed-Solomon scheme should be used to correct errors in the real-time communication environment. The proposed scheme utilizes the cache effectively, thus preventing reset of the entire decoding process and allowing real-time multimedia applications to meet their deadline constraints. Simulation results show that the PRSB greatly improves the overall playback quality of a video.