This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols, and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies, and Internet protocols. The basic premise is to have smart sensors collaborate directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile, and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols, and applications. Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services.

Internet of Things: A Survey on Enabling Technologies, Protocols, and Applications

Millimeter wave (mmWave) signals experience orders-of-magnitude more pathloss than the microwave signals currently used in most wireless applications and all cellular systems. MmWave systems must therefore leverage large antenna arrays, made possible by the decrease in wavelength, to combat pathloss with beamforming gain. Beamforming with multiple data streams, known as precoding, can be used to further improve mmWave spectral efficiency. Both beamforming and precoding are done digitally at baseband in traditional multi-antenna systems. The high cost and power consumption of mixed-signal devices in mmWave systems, however, make analog processing in the RF domain more attractive. This hardware limitation restricts the feasible set of precoders and combiners that can be applied by practical mmWave transceivers. In this paper, we consider transmit precoding and receiver combining in mmWave systems with large antenna arrays. We exploit the spatial structure of mmWave channels to formulate the precoding/combining problem as a sparse reconstruction problem. Using the principle of basis pursuit, we develop algorithms that accurately approximate optimal unconstrained precoders and combiners such that they can be implemented in low-cost RF hardware. We present numerical results on the performance of the proposed algorithms and show that they allow mmWave systems to approach their unconstrained performance limits, even when transceiver hardware constraints are considered.

Spatially Sparse Precoding in Millimeter Wave MIMO Systems

Millimeter wave (mmWave) holds promise as a carrier frequency for fifth generation cellular networks. Because mmWave signals are sensitive to blockage, prior models for cellular networks operated in the ultra high frequency (UHF) band do not apply to analyze mmWave cellular networks directly. Leveraging concepts from stochastic geometry, this paper proposes a general framework to evaluate the coverage and rate performance in mmWave cellular networks. Using a distance-dependent line-of-site (LOS) probability function, the locations of the LOS and non-LOS base stations are modeled as two independent non-homogeneous Poisson point processes, to which different path loss laws are applied. Based on the proposed framework, expressions for the signal-to-noise-and-interference ratio (SINR) and rate coverage probability are derived. The mmWave coverage and rate performance are examined as a function of the antenna geometry and base station density. The case of dense networks is further analyzed by applying a simplified system model, in which the LOS region of a user is approximated as a fixed LOS ball. The results show that dense mmWave networks can achieve comparable coverage and much higher data rates than conventional UHF cellular systems, despite the presence of blockages. The results suggest that the cell size to achieve the optimal SINR scales with the average size of the area that is LOS to a user.

Coverage and Rate Analysis for Millimeter-Wave Cellular Networks

LTE Release 8 is one of the primary broadband technologies based on OFDM, which is currently being commercialized. LTE Release 8, which is mainly deployed in a macro/microcell layout, provides improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operation and seamless integration with existing systems. LTE-Advanced (also known as LTE Release 10) significantly enhances the existing LTE Release 8 and supports much higher peak rates, higher throughput and coverage, and lower latencies, resulting in a better user experience. Additionally, LTE Release 10 will support heterogeneous deployments where low-power nodes comprising picocells, femtocells, relays, remote radio heads, and so on are placed in a macrocell layout. The LTE-Advanced features enable one to meet or exceed IMT-Advanced requirements. It may also be noted that LTE Release 9 provides some minor enhancement to LTE Release 8 with respect to the air interface, and includes features like dual-layer beamforming and time-difference- of-arrival-based location techniques. In this article an overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed. This includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, uplink spatial multiplexing including extension to four-layer MIMO, and heterogeneous networks with emphasis on Type 1 and Type 2 relays. Finally, the performance of LTEAdvanced using IMT-A scenarios is presented and compared against IMT-A targets for full buffer and bursty traffic model.

LTE-advanced: next-generation wireless broadband technology [Invited Paper]

Due to the broadcast nature of radio propagation, the wireless air interface is open and accessible to both authorized and illegitimate users. This completely differs from a wired network, where communicating devices are physically connected through cables and a node without direct association is unable to access the network for illicit activities. The open communications environment makes wireless transmissions more vulnerable than wired communications to malicious attacks, including both the passive eavesdropping for data interception and the active jamming for disrupting legitimate transmissions. Therefore, this paper is motivated to examine the security vulnerabilities and threats imposed by the inherent open nature of wireless communications and to devise efficient defense mechanisms for improving the wireless network security. We first summarize the security requirements of wireless networks, including their authenticity, confidentiality, integrity, and availability issues. Next, a comprehensive overview of security attacks encountered in wireless networks is presented in view of the network protocol architecture, where the potential security threats are discussed at each protocol layer. We also provide a survey of the existing security protocols and algorithms that are adopted in the existing wireless network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term evolution (LTE) systems. Then, we discuss the state of the art in physical-layer security, which is an emerging technique of securing the open communications environment against eavesdropping attacks at the physical layer. Several physical-layer security techniques are reviewed and compared, including information-theoretic security, artificial-noise-aided security, security-oriented beamforming, diversity-assisted security, and physical-layer key generation approaches. Since a jammer emitting radio signals can readily interfere with the legitimate wireless users, we also introduce the family of various jamming attacks and their countermeasures, including the constant jammer, intermittent jammer, reactive jammer, adaptive jammer, and intelligent jammer. Additionally, we discuss the integration of physical-layer security into existing authentication and cryptography mechanisms for further securing wireless networks. Finally, some technical challenges which remain unresolved at the time of writing are summarized and the future trends in wireless security are discussed.

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A Survey on Wireless Security: Technical Challenges, Recent Advances, and Future Trends

A wireless communication system (100) and method for providing high speed uplink packet access from user equipment (128, 130) to a base station (114, 116, 118, 120). Each user equipment (128, 130) and base station (114, 116, 118, 120) includes a transmitter (1106, 1206), a receiver (1104, 1204), and a controller (1108, 1208). The user equipment (128, 130) transmits data packets to the base station (114, 116, 118, 120). The base station transmits control information, corresponding to the data packets, to the user equipment (128, 130). The control information includes a busy bit to disable uplink transmission of a transmitter (1106) of the user equipment (123,130).

System and method for downlink signaling for high speed uplink packet access

To address the need to convey ACK/NACK information in a manner that conserves system and signaling resources, embodiments of the present invention employ a Node-B transmitting on two types of ACK/NACK broadcast channels ( 501, 502 ), one type for received uplink data that was scheduled by the Node B and the other type of broadcast channel for received uplink data that was not scheduled by the Node B. Other embodiments of the invention employ a Node-B transmitting on two types of broadcast channels, one type of broadcast channel for received uplink data that comes from non-SHO users and another type of broadcast channel for received uplink data that comes from non-scheduled users or comes from scheduled SHO users. In addition, ACK/NACK information is scheduled ( 800 ) into the available broadcast channel time slots in accordance with a transmission priority that is determined by a scheduler.

Acknowledgement method for ACK/NACK signaling to facilitate UE uplink data transfer

Comprehensive long term evolution of the Universal Mobile Telecommunications System (UMTS) specifications is currently ongoing to provide significant improvement over the current release. Important goals for the evolved system include significantly improved system capacity and coverage, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To ensure low latency, users must be able to establish a connection to the network quickly. This paper provides a preliminary design and procedure for the random access channel used to establish a connection when the mobile is not yet time-synchronized to the network in the uplink.

Random Access Design for UMTS Air-Interface Evolution

To address the need for a resource allocation scheme that results in a better tradeoff between cell-edge performance and overall spectral efficiency, a communication system (100) is provided that allocates uplink transmit power to user equipment (UEs) (102, 104) based on a fractional power control scheme (300). In another embodiment, since the cell-edge users are also likely to be power limited, the communication system may implement a minimized uplink transmission bandwidth resource allocation scheme (404, 406, 408, 410, 412, 414) that may work with the fractional power control scheme to achieve a level of performance desired for uplink transmissions in 3GPP (Third Generation Partnership Project) and 3GPP2 Evolution communication systems.

Method and apparatus for uplink resource allocation in a frequency division multiple access communication system

A communication is provided that schedules both Distributed Virtual Resource Blocks (DVRB) and Localized Virtual Resource Blocks (LVRB) in a same frequency channel, thereby obtaining the benefits of frequency selective scheduling while minimizing the uplink feedback overhead. In one embodiment of the invention, the communication system assigns one or more downlink Physical Resource Blocks (PRBs) of multiple downlink Physical Resource Blocks (PRBs) to each user equipment (UE) given an LVRB to produce at least one reserved PRB and multiple non-reserved PRBs and assigns a part of each PRB of the multiple non-reserved PRBs to a UE given a DVRB. In another embodiment of the invention, the communication system assigns PRBs pre-reserved for localized transmission to UEs scheduled for LVRBs and assigns parts of multiple PRBs pre-reserved for distributed transmission to each UE given a DVRB.

Rapeepat Ratasuk

Papers

System and method for downlink signaling for high speed uplink packet access

Acknowledgement method for ACK/NACK signaling to facilitate UE uplink data transfer

Random Access Design for UMTS Air-Interface Evolution

Method and apparatus for uplink resource allocation in a frequency division multiple access communication system

Method and apparatus for downlink resource allocation in an orthogonal frequency division multiplexing communication system