Bernhard Raaf

Bio: Bernhard Raaf is an academic researcher from Intel. The author has contributed to research in topics: Base station & Relay. The author has an hindex of 35, co-authored 352 publications receiving 4766 citations. Previous affiliations of Bernhard Raaf include Nokia Networks & Nokia.

In-vehicle authorization for autonomous vehicles

Abstract: Technologies for authorizing a passenger of an autonomous vehicle include determining a passenger authorization policy based on a request for a taxi service and determining whether a passenger is authorized for the taxi service based on the passenger authorization policy. The passenger authorization policy may include a set of rules for authorizing a passenger based on the request for the taxi service and/or a global authorization policy. For example, the passenger may be authorized based on the identity of the passenger, the number of passengers, the age of the passenger, an authentication token, and/or other methodologies. The passenger authorization policy may be generated by the autonomous vehicle in response to the request for a taxi service or received from a passenger authorization management server as part of the request for the taxi service.

Relaying in a communication system

Abstract: A communication link is provided between a station of an access system and a relay node. The relay node is a node capable of wirelessly communicating with at least one communication device within the coverage thereof. A set up procedure for the communication link is initiated such that the relay node acts as a communication device towards the station, the set up procedure being initiated according to a set up procedure between the station and communication devices accessing the station directly. Communication between the relay node and at least one communication device within the coverage area thereof are handled such that the relay nodes acts as a station of an access system towards said at least one communication device.

Methods and devices for radio communications

Abstract: A circuit arrangement includes a preprocessing circuit configured to obtain context information related to a user location, a learning circuit configured to determine a predicted user movement based on context information related to a user location to obtain a predicted route and to determine predicted radio conditions along the predicted route, and a decision circuit configured to, based on the predicted radio conditions, identify one or more first areas expected to have a first type of radio conditions and one or more second areas expected to have a second type of radio conditions different from the first type of radio conditions and to control radio activity while traveling on the predicted route according to the one or more first areas and the one or more second areas.

Effect of Relaying on Coverage in 3GPP LTE-Advanced

Abstract: Current broadband wireless networks are characterized by large cell sizes. Yet, even in advanced networks that will be built using 3 GPP Long Term Evolution (LTE), also referred to as 3GPP LTE-Advanced, or mobile WiMAX radio interface, users on the cell edge will face relatively low signal-to-interference-plus-noise-ratio (SINR). An attractive solution for this problem is provided by multihop technologies. In this paper we consider the feasibility of Decode and Forward (DF) Relay Nodes (RNs) from 3GPP LTE-Advanced perspective. We propose a novel evaluation methodology that can be used to find a relation of RN transmission power, ratio between number of Base Stations (BSs) and RNs, and performance of the system. Evaluation of DF relays in 3GPP LTE-Advanced framework indicates a good performance gain.

Data transmission method

Abstract: The invention relates to a method for transmitting data between a transmitter and a receiver via a wireless data channel of a communication network (CN). The transmitter transmits data to the receiver, where the transmission includes at least one transmission parameter which is selected based on a first channel quality that is known to the transmitter. The receiver receives the data, and the receiver determines the first channel quality known to the transmitter from said data via the at least one used transmission parameter as well as a second, current channel quality via the quality of the received data; and the receiver compares the first channel quality with the second channel quality.

Millimeter-Wave Cellular Wireless Networks: Potentials and Challenges

Abstract: Millimeter-wave (mmW) frequencies between 30 and 300 GHz are a new frontier for cellular communication that offers the promise of orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multielement antenna arrays. This paper surveys measurements and capacity studies to assess this technology with a focus on small cell deployments in urban environments. The conclusions are extremely encouraging; measurements in New York City at 28 and 73 GHz demonstrate that, even in an urban canyon environment, significant non-line-of-sight (NLOS) outdoor, street-level coverage is possible up to approximately 200 m from a potential low-power microcell or picocell base station. In addition, based on statistical channel models from these measurements, it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities. Cellular systems, however, will need to be significantly redesigned to fully achieve these gains. Specifically, the requirement of highly directional and adaptive transmissions, directional isolation between links, and significant possibilities of outage have strong implications on multiple access, channel structure, synchronization, and receiver design. To address these challenges, the paper discusses how various technologies including adaptive beamforming, multihop relaying, heterogeneous network architectures, and carrier aggregation can be leveraged in the mmW context.

A survey on 3GPP heterogeneous networks

Abstract: As the spectral efficiency of a point-to-point link in cellular networks approaches its theoretical limits, with the forecasted explosion of data traffic, there is a need for an increase in the node density to further improve network capacity. However, in already dense deployments in today's networks, cell splitting gains can be severely limited by high inter-cell interference. Moreover, high capital expenditure cost associated with high power macro nodes further limits viability of such an approach. This article discusses the need for an alternative strategy, where low power nodes are overlaid within a macro network, creating what is referred to as a heterogeneous network. We survey current state of the art in heterogeneous deployments and focus on 3GPP LTE air interface to describe future trends. A high-level overview of the 3GPP LTE air interface, network nodes, and spectrum allocation options is provided, along with the enabling mechanisms for heterogeneous deployments. Interference management techniques that are critical for LTE heterogeneous deployments are discussed in greater detail. Cell range expansion, enabled through cell biasing and adaptive resource partitioning, is seen as an effective method to balance the load among the nodes in the network and improve overall trunking efficiency. An interference cancellation receiver plays a crucial role in ensuring acquisition of weak cells and reliability of control and data reception in the presence of legacy signals.

Heterogeneous Cellular Networks with Flexible Cell Association: A Comprehensive Downlink SINR Analysis

Abstract: In this paper we develop a tractable framework for SINR analysis in downlink heterogeneous cellular networks (HCNs) with flexible cell association policies. The HCN is modeled as a multi-tier cellular network where each tier's base stations (BSs) are randomly located and have a particular transmit power, path loss exponent, spatial density, and bias towards admitting mobile users. For example, as compared to macrocells, picocells would usually have lower transmit power, higher path loss exponent (lower antennas), higher spatial density (many picocells per macrocell), and a positive bias so that macrocell users are actively encouraged to use the more lightly loaded picocells. In the present paper we implicitly assume all base stations have full queues; future work should relax this. For this model, we derive the outage probability of a typical user in the whole network or a certain tier, which is equivalently the downlink SINR cumulative distribution function. The results are accurate for all SINRs, and their expressions admit quite simple closed-forms in some plausible special cases. We also derive the average ergodic rate of the typical user, and the minimum average user throughput - the smallest value among the average user throughputs supported by one cell in each tier. We observe that neither the number of BSs or tiers changes the outage probability or average ergodic rate in an interference-limited full-loaded HCN with unbiased cell association (no biasing), and observe how biasing alters the various metrics.

User Association for Load Balancing in Heterogeneous Cellular Networks

Abstract: For small cell technology to significantly increase the capacity of tower-based cellular networks, mobile users will need to be actively pushed onto the more lightly loaded tiers (corresponding to, e.g., pico and femtocells), even if they offer a lower instantaneous SINR than the macrocell base station (BS). Optimizing a function of the long-term rate for each user requires (in general) a massive utility maximization problem over all the SINRs and BS loads. On the other hand, an actual implementation will likely resort to a simple biasing approach where a BS in tier j is treated as having its SINR multiplied by a factor Aj ≥ 1, which makes it appear more attractive than the heavily-loaded macrocell. This paper bridges the gap between these approaches through several physical relaxations of the network-wide association problem, whose solution is NP hard. We provide a low-complexity distributed algorithm that converges to a near-optimal solution with a theoretical performance guarantee, and we observe that simple per-tier biasing loses surprisingly little, if the bias values Aj are chosen carefully. Numerical results show a large (3.5x) throughput gain for cell-edge users and a 2x rate gain for median users relative to a maximizing received power association.

User Association for Load Balancing in Heterogeneous Cellular Networks

Abstract: For small cell technology to significantly increase the capacity of tower-based cellular networks, mobile users will need to be actively pushed onto the more lightly loaded tiers (corresponding to, e.g., pico and femtocells), even if they offer a lower instantaneous SINR than the macrocell base station (BS). Optimizing a function of the long-term rates for each user requires (in general) a massive utility maximization problem over all the SINRs and BS loads. On the other hand, an actual implementation will likely resort to a simple biasing approach where a BS in tier j is treated as having its SINR multiplied by a factor A_j>=1, which makes it appear more attractive than the heavily-loaded macrocell. This paper bridges the gap between these approaches through several physical relaxations of the network-wide optimal association problem, whose solution is NP hard. We provide a low-complexity distributed algorithm that converges to a near-optimal solution with a theoretical performance guarantee, and we observe that simple per-tier biasing loses surprisingly little, if the bias values A_j are chosen carefully. Numerical results show a large (3.5x) throughput gain for cell-edge users and a 2x rate gain for median users relative to a max received power association.