Kurzbeschreibung
(Englisch)
|
In this project we consider next generation WLANs where we focus on high node density, data rates from 1Mbps to 1Gbps, frequencies beyond 5GHz and low mobility leading to a poor scattering / high array situation. To achieve the required scalability and spectral efficiency our approach will introduce cooperative signalling in combination with spatial multiplexing and channel adaptive scheduling. This jointly introduces two major breakthroughs: a) exploiting spatial multiplexing in poor scattering channels and b) exploiting adaptive scheduling in low mobility. To open up the benefits of this combination our work will comprise multimode/multihop channel modelling, efficient cooperative spatial multiplexing, cooperative medium access and cooperative channel adaptive scheduling schemes.
|
Partner und Internationale Organisationen
(Englisch)
|
BE, BG, CZ, FR, DE, EL, HU, IT, MT, NO, PT, RO, CS, SK, ES, SE, CH, TR, UK
|
Abstract
(Englisch)
|
Next generation of Wireless Local Area Networks (WLANs) will accommodate het-erogeneous nodes with data rate requirements ranging from 1Mbps to 1Gbps. For complexity reasons low end user nodes will have a single antenna. High end user nodes will feature multiple antennas to improve throughput and coverage. The ex-tended use and range of deployment will lead to a high node density. This makes cooperative signalling schemes an extremely attractive option. Channel adaptive scheduling, adaptive modulation and spatial multiplexing (MIMO) will be indispen-sable to achieve the required scalability and spectral efficiency. The heterogeneous quality of service requirements would facilitate channel adaptive scheduling, but typical user nodes in WLANs have low mobility and the channel may not vary suffi-ciently over time to make fair channel adaptive scheduling efficient. For spectral reasons next generation WLANs will operate beyond 5 GHz (e.g. at 17/24GHz). Here we face a poor scattering/rich array situation as opposed to the rich scattering/poor array situation at 5GHz. The potential of cooperative signalling (in particular linear multi-node relaying) to exploit spatial multiplexing on poor scattering channels has already been showed in previous works. The main motivation of this COST project is to open up the benefits of cooperative diversity, channel adaptive scheduling and spatial multiplexing (MIMO) in a low mobility environment with poor scattering and with heterogeneous nodes. This area was essentially unexplored to date and required fundamental new work ranging from multinode/multihop channel modelling to efficient cooperative spatial multiplexing, cooperative medium access and cooperative channel adaptive scheduling schemes. In this project we constrained our attention to linear but possibly time-variant proc-essing at the cooperating nodes. This has the major advantage that the cooperation is transparent to an adaptive modulation scheme (symbol alphabet) used by the source. We were interested in schemes that allow a seamless integration of multi-antenna nodes and that remain efficient in a poor scattering environment. Our work includes five workpackages. The first workpackage aims at characterizing and measuring the multihop/multinode channel. We use for this our RACOON Lab and testbed infrastructure which constitutes a heavy investment of ETH in cooperative wireless. The second workpackage contains fundamental results on performance bounds. From the results of the first workpackages we obtain reference perform-ances that are used in the third workpackage, where we focus on relay gain and power allocation and signal processing at the nodes. The fourth workpackage deals with link level aspects of the communication protocol. We study the use of linear scalable dispersion codes to exploit the diversity factors of the system. Finally the fifth workpackage treats channel adaptive scheduling and multiplexing issues. We proposed in this framework among others a joint cooperative diversity and schedul-ing scheme that achieves multiuser diversity gains.
|
