231 research outputs found
Control Aware Radio Resource Allocation in Low Latency Wireless Control Systems
We consider the problem of allocating radio resources over wireless
communication links to control a series of independent wireless control
systems. Low-latency transmissions are necessary in enabling time-sensitive
control systems to operate over wireless links with high reliability. Achieving
fast data rates over wireless links thus comes at the cost of reliability in
the form of high packet error rates compared to wired links due to channel
noise and interference. However, the effect of the communication link errors on
the control system performance depends dynamically on the control system state.
We propose a novel control-communication co-design approach to the low-latency
resource allocation problem. We incorporate control and channel state
information to make scheduling decisions over time on frequency, bandwidth and
data rates across the next-generation Wi-Fi based wireless communication links
that close the control loops. Control systems that are closer to instability or
further from a desired range in a given control cycle are given higher packet
delivery rate targets to meet. Rather than a simple priority ranking, we derive
precise packet error rate targets for each system needed to satisfy stability
targets and make scheduling decisions to meet such targets while reducing total
transmission time. The resulting Control-Aware Low Latency Scheduling (CALLS)
method is tested in numerous simulation experiments that demonstrate its
effectiveness in meeting control-based goals under tight latency constraints
relative to control-agnostic scheduling
RESOURCE ALLOCATION IN 802.11AX NETWORKS
Methods of selection of Voice over Internet Protocol (VoIP), video and other users to meet quality of service (QoS) goals and optimize overall performance in 802.11ax networks are provided. These methods allow policy based decisions such as controlling the number of video, VoIP or other users or sub-channel sizes for video (or other) users or deciding data rate (or associated modulation and coding scheme) for each user in each scheduling interval (SI), and allow dynamic decisions for the value of the SI
Performance Enhancement of IEEE 802.11AX in Ultra-Dense Wireless Networks
IEEE 802.11ax, which is one emerging WLAN standard, aims at providing highly efficient communication in ultra-dense wireless networks. However, due to a large number of stations (STAs) in dense deployment scenarios and diverse services to be supported, there are many technical challenges to be overcome. Firstly, the potential high packet collision rate significantly degrades the network efficiency of WLAN. In this thesis, we propose an adaptive station (STA) grouping scheme to overcome this challenge in IEEE 802.11ax using Uplink OFDMA Random Access (UORA). In order to achieve optimal utilization efficiency of resource units (RUs), we first analyze the relationship between group size and RU efficiency. Based on this result, an adaptive STA grouping algorithm is proposed to cope with the performance fluctuation of 802.11ax due to remainder stations after grouping. The analysis and simulation results demonstrate that our adaptive grouping algorithm dramatically improves the performance of both the overall system and each STA in the ultra-dense wireless network.
Meanwhile, due to the limited RU efficiency of UORA, we adopt the proposed grouping scheme in the Buffer State Report (BSR) based two-stage mechanism (BTM) to enhance the Uplink (UL) Multi-user (MU) access in 802.11ax. Then we propose an adaptive BTM grouping scheme. The analysis results of average RU for each STA, average throughput of the whole system and each STA are derived. The numerical results show that the proposed adaptive grouping scheme provides 2.55, 413.02 and 3712.04 times gains in throughput compared with the UORA grouping, conventional BTM, and conventional UORA, respectively.
Furthermore, in order to provide better QoS experience in the ultra-dense network with diverse IoT services, we propose a Hybrid BTM Grouping algorithm to guarantee the QoS requirement from high priority STAs. The concept of ``QoS Utility is introduced to evaluate the satisfaction of transmission. The numerical results demonstrate that the proposed Hybrid BTM grouping scheme has better performance in BSR delivery rate as well as QoS utility than the conventional BTM grouping
EFFICIENT FINE-GRAINED 802.11AX BSR-BASED OFDMA RU ALLOCATION
Proposed herein are techniques that provide a simple Institute of Electrical and Electronics Engineers (IEEE) 802.11ax (WiFi6®) uplink (UL) orthogonal frequency-division multiple access (OFDMA) throughput improvement by exploiting existing standards and enterprise traffic patterns
Cascaded WLAN-FWA Networking and Computing Architecture for Pervasive In-Home Healthcare
Pervasive healthcare is a promising assisted-living solution for chronic
patients. However, current cutting-edge communication technologies are not able
to strictly meet the requirements of these applications, especially in the case
of life-threatening events. To bridge this gap, this paper proposes a new
architecture to support indoor healthcare monitoring, with a focus on epileptic
patients. Several novel elements are introduced. The first element is the
cascading of a WLAN and a cellular network, where IEEE 802.11ax is used for the
wireless local area network to collect physiological and environmental data
in-home and 5G-enabled Fixed Wireless Access links transfer them to a remote
hospital. The second element is the extension of the network slicing concept to
the WLAN, and the introduction of two new slice types to support both regular
monitoring and emergency handling. Moreover, the inclusion of local computing
capabilities at the WLAN router, together with a mobile edge computing
resource, represents a further architectural enhancement. Local computation is
required to trigger not only health-related alarms, but also the network
slicing change in case of emergency: in fact, proper radio resource scheduling
is necessary for the cascaded networks to handle healthcare traffic together
with other promiscuous everyday communication services. Numerical results
demonstrate the effectiveness of the proposed approach while highlighting the
performance gain achieved with respect to baseline solutions
- …