Remote Attestation is emerging as a promising technique to ensure that some remote device is in a trustworthy state. This can for example be an IoT device that is attested by a cloud service before allowing the device to connect. However, flaws in the communication protocols associated with the remote attestation mechanism can introduce vulnerabilities into the system design and potentially nullify the added security. Formal verification of protocol security can help to prevent such flaws. In this work we provide a detailed analysis of the necessary security properties for remote attestation focusing on the authenticity of the involved agents. We extend beyond existing work by considering the possibility of an attestation server (making the attestation process involve three parties) as well as requiring verifier authentication. We demonstrate that some security properties are not met by a state-of-the-art commercial protocol for remote attestation for our strong adversary model. Moreover, we design two new communication protocols for remote attestation that we formally prove fulfil all of the considered authentication properties.

Despite the clear dominance of video streaming traffic on the Internet and the significant ramifications of disclosure of which videos users are streaming, video fingerprinting has received relatively little attention compared to other traffic analysis domains. Existing attacks are tailored to undefended traffic and mostly rely on a few manually crafted features. Meanwhile, potential defenses are ad hoc, often impractical, and typically only mentioned briefly. Drawing from progress made on website fingerprinting, we aim to improve current standards for attacks and defenses for video streaming traffic while highlighting a critical and underexplored issue on today's Internet. We show that directional and timing-based attacks that leverage CNNs are competitive with state-of-the-art video fingerprinting attacks, in many cases with far less training data. We also provide the first extensive study of potential defenses, which considers performance against attacks, overheads, and user QoE; and we present a novel defense design that boasts both broader applicability and greater efficacy than existing proposals.

Providing authenticated interactions is a key responsibility of most cryptographic protocols. When designing new protocols with strict security requirements it is therefore essential to formally verify that they fulfil appropriate authentication properties. We identify a gap in the case of protocols with unilateral (one-way) authentication, where existing properties are poorly adapted. In existing work, there is a preference for defining strong authentication properties, which is good in many cases but not universally applicable. In this work we make the case for weaker authentication properties. In particular, we investigate one-way authentication and extend Lowe's authentication hierarchy with two such properties. We formally prove the relationship between the added and existing properties. Moreover, we demonstrate the usefulness of the added properties in a case study on remote attestation protocols. This work complements earlier work with additional generic properties that support formal verification of a wider set of protocol types.

Multi-stage interference cancellation (IC) can improve the interference conditions for all users of a cell. In order to exploit the IC gain at system level, it is important to design radio resource management algorithms that account for this gain. For this purpose, two new load control algorithms are proposed in this paper, together with some further enhancements. For Algorithm 1, load control and scheduling are still performed based on the air interface Rise over Thermal (RoT), but with an increased RoT target. The RoT target is determined based on the estimated IC gain. A cell-specific and dynamic RoT target is hence used rather than a constant one. With Algorithm 2, load control and scheduling are performed based on an effective RoT without increasing the RoT target. The load control function is placed after an intermediate IC stage depending on the timing constraints and/or the required IC processing gain of the coverage limiting channels. With the proposed algorithms, system-level simulation results show that the average cell throughput can be considerably improved and at the same time the coverage can be maintained at a level similar to a system without IC.

Uplink co-ordinated multipoint reception (UL CoMP) has received attention recently, especially for LTE Advanced, due to its promise of increasing spectral efficiency. In this paper, UL CoMP for HSPA networks is considered. UL CoMP for HSPA may be deployed without changes to the standard, and may be applied also for legacy UEs. Comparisons and contrasts of CoMP with conventional soft/soft handover are discussed as well as practical receiver structures incorporating antenna selection within the pool of antennas available in a CoMP cell. Radio resource management issues are discussed including mobility, power control, load control, and scheduling. It is concluded that UL CoMP requires only minimal changes to these algorithms. In a practical scenario, gains in cell-edge throughput of at least 118% and 144% are demonstrated for CoMP-3 and CoMP-6, respectively, for the case of full buffer traffic. The gains are even larger for the case of short files uploads where the conventional network suffers from the inability to exploit soft/softer handover due to latencies involved in updating a UE's active set.

Future cellular networks are expected to provide significantly higher capacity than today's systems. This might require a denser access point deployment, with a potential increase in network deployment cost as a consequence. A promising way to reduce cost is a multi-hop deployment where wireless relay nodes (RN) are introduced to enhance capacity and coverage. In this paper, a deployment procedure for a static radio environment is considered, adding RNs incrementally as a complement to initially deployed macro base stations (BS). Different strategies of deploying BSs and RNs, providing equal service levels, are analyzed from a cost perspective. We develop a methodology that can determine and compare the most cost efficient deployment mixes of BSs and RNs. Further, we compare a deployment of macro BSs and relays with a deployment of macro BSs and micro BSs. Results show that relays are more cost efficient if the micro BS cost is between 10 and 15 % higher compared to the cost of an RN.

This paper presents a novel ARQ scheme for multiple unicast flows in a multi-user system, which enhances the aggregate throughput efficiency. The core idea is to exploit knowledge of previously overheard packets by unintended users, and perform wise selection and joint encoding of any retransmitted information. Intended users may decode the jointly encoded packet by exploiting the previously overheard packets. It is found that the throughput efficiency in a K-user system approaches, the fairly remarkable result of, unit value when K goes to infinity. Moreover, complexity and overhead of the scheme is studied and a link to (feedback free) network coding is established

In this paper, bi-directional traffic between two nodes communicating via a relay node is considered. A novel relaying method based on joint data packet encoding in conjunction with exploitation of a priori known information is presented. Moreover, a specially crafted method for combining of the direct and relayed radio signal is suggested. The proposed scheme enables a reduced number of transmissions, whereby enhancing aggregate throughput. Evaluation, where optimal power and rate settings are derived, shows that the proposed method enhances the throughput up to 33% as compared to a (traditional) four-phase bi-directional protocol under a system energy constraint, both with and without the proposed combining method

Multihop packet radio networking promises increased data rates and enhanced coverage in wireless networks. In this paper, we propose a new high performing low complexity multihop forwarding scheme, denoted multiuser diversity forwarding (MDF), that efficiently exploits inherent radio channel characteristics. The scheme is founded on a cross-layer paradigm, which enables a transmitting node to perform instant rate adaptation as well as to select among relays and among flows, thereby taking full advantage of the inherent multiuser diversity. The relative performance of MDF is benchmarked against two reference schemes, nearest with forward progress (NFP) and selection diversity forwarding (SDF). The simulations indicate that the proposed scheme yields a substantial throughput increase.

The emerging Bluetooth technology enables devices to be wirelessly connected in an ad hoc fashion. Using Bluetooth, devices are organized into small piconets, which in turn may be inter-connected to form larger networks called scatternets. In a scatternet, some of the devices participate in more than one piconet. These nodes are called PMP (Participant in Multiple Piconets) nodes. Since a Bluetooth unit only hence one transceiver, it may only be active in one piconet at any given instant and hance a PMP node must schedule its time between piconets on a time-division basis. The availability of PMP nodes represents an important performance constraint when building scatternets and has to be effectively coordinated between the different piconets. To allow flexible and efficient scatternet operation and to overcome the shortcomings of the current Bludetooth modes, we proposed a new mode---JUMP mode. This mode includes a set of communication rules that enable efficient scatternet operation by offering a great deal of flexibility for a node to adapt its activity in different piconets to the traffic conditions. Using JUMP mode a PMP node divides the time into timewindows and then signals about which piconet to be present in for each of these time windows. The time windows are of pseudo random length to eliminate systematic collisions and thereby avoid starvation and live-lock problems without any need for scatternet-wide may coordination. Besides enabling scatternet operation, JUMP mode also enhance other aspects of Bluetooth , such as low-power operation

The current research and development of short range radio technologies will provide new means to implement ad-hoc networking between cellular phones, notebook computers, and small, low powered devices such as electronic calendars. An industry consortium has recently released preliminary specifications for a short range radio technology named Bluetooth. The Bluetooth radio operates in the unlicensed ISM band at 2.4 GHz with a transmission power in the range of -30-20 dBm. The Bluetooth radio nodes form ad-hoc networks called piconets, each of which offers a gross bit rate of 1 Mbps and allows a mix of voice and data communication channels. This study presents a number of different network usage cases for Bluetooth ad-hoc piconets and a subset of these scenarios is further analysed by means of simulations. A mix of data traffic and voice traffic is used in the simulations, where the data traffic streams are modelled with IBP processes. A worst case laptop conference scenario is simulated to stress the robustness of the Bluetooth system under very high load and bursty traffic conditions. Moreover, simulations are also made with measured voice traffic to study a mixture of bursty data and voice packet traffic.