Research Tracks

Track I: Scalable Spatially Enabled Wireless Post-Cellular Network

Cellular Relaying

Classical cellular networks exploit the path loss to spatially reuse the same bandwidth at some distance. Their performance in theory scales linearly with the number of base stations. In practice however the scalability is severely limited by the spatial reuse: Exploiting the path loss implies that a base station has to be spatially closer to the users it serves than to the users it interferes with, leading to a cellular network topology. Thus to increase network capacity in areas where it is most needed, we would have to identify additional base station sites in areas with high user density. This frequently turns out to be impossible.

From theory we know that infrastructureless ad hoc networks can support a sum rate in the network, which grows up to linearly with the number of nodes. Appropriate schemes, such as hierarchical MIMO, are based on distributed spatial multiplexing. While their scaling in the number of nodes is favorable, their complexity tends to become prohibitive in large networks, especially if we utilize cooperation among mobile users.

The presence of dedicated stationary infrastructureless nodes (relays) can substantially reduce system complexity while preserving the favorable scaling. Given the paramount importance of the number of nodes, we need to understand the tradeoff between node complexity and node density and we need to design scalable algorithms, which are specifically optimized for cooperation involving low complexity nodes. The complexity-density tradeoff and related signaling protocols are essentially unexplored to date in our field.

More details can be found here.


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Track II: Ubiquitous non-intrusive and infrastructureless wireless posture capturing

UWB Rx FPGA Board

A huge range of applications is enabled by knowing the posture of a person and being able to track its motions. In professional and leisure sports training this information can be used to optimize training efficiency and to provide instantaneous feedback to the athlete. Rehabilitation can be optimized by monitoring progress, analyzing wrong movement patterns and supervising exercises. In everyday life, we can reduce long term ailments such as chronic back pain by detecting malpositions and advising the user accordingly. For elderly persons that live on their own, reliable fall detection and subsequent call for help will mitigate a paramount concern and vastly improve autonomy and quality of life.
If we go one step further and include actuators which induce protective movements of limbs (for example by stimulating the contraction of specific muscles), we could even mitigate the consequences of a fall without requiring bulky equipment to be worn. For these and for many other applications it would in addition be beneficial to have some information about the environment in order to optimize the induced reaction.

More details can be found here.


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Track III: Micro-sphere (swarm) wireless networks for joint communication, localization and enforced movement

RFID Chips

We consider a dense network of hundreds or thousands of sub-mm size sensors/actors. These nodes (tags) have extremely low complexity and are powered wirelessly (i.e. operate in an RFID-like fashion). The nodes are smart, i.e. they comprise some electronics of limited complexity. The network is highly asymmetric, there may be one or more external high complexity nodes (readers) complementing the swarm of tags. Our goals are fivefold: (i) wirelessly supply power to the tags, (ii) enable communication in between the nodes and between nodes and readers, (iii) localize the nodes with respect to each other and in a global coordinate system with sub-mm accuracy, (iv) intentionally generate directed forces to specific nodes in order to initiate a specific movement (e.g. in order to make a subset of nodes move closer, or to orient a subset of nodes in a specific direction) and (v) implement a specific energy absorption profile in the swarm (this feature can be used to generate a location specific temperature profile such as required by thermal tumor therapy). A system of this type has applications in such diverse fields as medical diagnosis and therapy, smart matter, physics, measurement and biology (swarm behavior) to name a few.

More details can be found here.

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