Toward Open Integrated Access and Backhaul with O-RAN

Millimeter wave (mmWave) communications has been recently standardized for use in the fifth generation (5G) of cellular networks, fulfilling the promise of multi-gigabit mobile throughput of current and future mobile radio network generations. In this context, the network densification required to overcome the difficult mmWave propagation will result in increased deployment costs. Integrated Access and Backhaul (IAB) has been proposed as an effective mean of reducing densification costs by deploying a wireless mesh network of base stations, where backhaul and access transmissions share the same radio technology. However, IAB requires sophisticated control mechanisms to operate efficiently and address the increased complexity. The Open Radio Access Network (RAN) paradigm represents the ideal enabler of RAN intelligent control, but its current specifications are not compatible with IAB. In this work, we discuss the challenges of integrating IAB into the Open RAN ecosystem, detailing the required architectural extensions that will enable dynamic control of 5G IAB networks. We implement the proposed integrated architecture into the first publiclyavailable Open-RAN-enabled experimental framework, which allows prototyping and testing Open-RAN-based solutions over end-to-end 5G IAB networks. Finally, we validate the framework with both ideal and realistic deployment scenarios exploiting the large-scale testing capabilities of publicly available experimental platforms

A General Methodology and Key Metrics For Scatternet Formation in Bluetooth

To fully exploit the capabilities of Bluetooth for the deployment of wireless ad-hoc networks, the scatternet concept has been proposed. A scatternet is constituted by an overlapping of simple structures named piconets, each composed of up to eight devices sharing the same radio channel. A scatternet may present different topological configurations, depending on the number of composing piconets, the role of the involved devices and the configuration of the links. This paper presents a general methodology for the scatternet formation and proposes metrics that can be used to evaluate a the scatternet performance. Several numerical examples are presented and discussed, highlighting the impact of metric selection on the scatternet performance

Locally Optimal Scatternet Topologies for Bluetooth Ad Hoc Networks

Bluetooth is a promising technology for personal/local area wireless communications. A Bluetooth scatternet is composed of overlapping piconets, each with a low number of devices sharing the same radio channel. This paper discusses the scatternet formation issue by analyzing topological characteristics of the scatternet formed. A matrix-based representation of the network topology is used to define metrics that are applied to evaluate the key cost parameters and the scatternet performance. Numerical examples are presented and discussed, highlighting the impact of metric selection on scatternet performance. Then, a distributed algorithm for scatternet topology optimization is introduced, that supports the formation of a "locally optimal" scatternet based on a selected metric. Numerical results obtained by adopting this distributed approach to optimize the network topology are shown to be close to the global optimum

A MAC protocol for Delay-Bounded applications in Wireless Sensor Networks

The problem of scheduling packet transmissions for data gathering in wireless sensor networks is studied in this paper. A scenario is considered where different sources contemporarily sense an event and signal the acquired information to a sink. Energy-latency tradeoffs for data gathering in sensor networks are explored by means of Integer Linear Programming Formulations. The objective of the optimization problems defined is to find minimum latency and minimum energy optimal data delivery trees, which are defined as aggregates of flows from multiple sources to a single receiver. A new distributed MAC protocol explicitly designed for Delay-Bounded Applications in Wireless Sensor Networks (DB-MAC) is also introduced. The primary objective of DB-MAC is to minimize the latency for delay bounded applications. Energy consumption is also reduced by means of a path aggregation mechanism that improves path sharing. Simulation results show that DB-MAC reduces the latency up to 70% with respect to a CSMA/CA MAC protocol, with up to 60% less transmissions. The performance of DBMAC is shown to be closer than CSMA/CA to the optimal values of latency and energy consumption

Distributed self-healing and variable topology optimization algorithms for QoS provisioning in scatternets

Bluetooth is an enabling technology for-Personal Area Networks. A scatternet is an ad hoc network created by interconnecting several Bluetooth piconets, each with at most eight devices. Each piconet uses a different radio channel constituted by a frequency hopping code. The way the devices are grouped in different piconets and the way the piconets are interconnected greatly affect the performance of the scatternet in terms of capacity, data transfer delay, and energy consumption. There is a need to develop distributed scatternet formation algorithms, which guarantee full connectivity of the devices, reconfigure the network due to mobility and failure of devices, and interconnect them such a way to create an optimal topology to achieve gainful performance. The contribution of this paper is to provide an integrated approach for scatternet formation and quality-of-service support (called SHAPER-OPT). To this aim, two main procedures are proposed. First, a new scatternet formation algorithm called self-healing algorithm producing multihop Bluetooth scatternets (SHAPER) is developed which forms tree-shaped scatternets. A procedure that produces a meshed topology applying a distributed scatternet optimization algorithm (DSOA) on the network built by SHAPER is then defined. Performance evaluation of the proposed algorithms, and of the accordingly created scatternets, is carried out by using ns2 simulation. Devices are shown to be able to join or leave the scatternet at any time, without compromising the long term connectivity. Delay for network setup and reconfiguration in dynamic environments is shown to be within acceptable bounds. DSOA is also shown to be easy to implement and to improve the overall network performance