Mobile broadband data usage in Long Term Evolution (LTE) networks is growing exponentially and capacity constraint is becoming an issue. Heterogeneous network, WiFi offload, and acquisition of additional radio spectrum can be used to address this capacity constraint. Licensed spectrum, however, is limited and can be costly to obtain. This paper investigates deploying LTE on a license-exempt band as part of the pico-cell underlay. Coexistence mechanism and other modifications to LTE are discussed. Performance analysis shows that LTE can deliver significant capacity even while sharing the spectrum with WiFi systems.

License-exempt LTE deployment in heterogeneous network

The IEEE 802.16 standard, commonly known as WiMAX, is the latest technology that has promised to offer broadband wireless access over long distance. Since 2001 WiMAX has evolved from 802.16 to 802.16d for fixed wireless access, and to the new IEEE 802.16e standard with mobility support. In this article we provide an overview of the state-of-the-art mobile WiMAX technology and its development. We focus our discussion on QoS provisioning and mobile WiMAX specification.

A Survey on Mobile WiMAX [Wireless Broadband Access]

A method of communicating through a random phase multiple access network is provided. A signal that has been spread using a pseudo-noise code and offset by a random timing offset and that contains payload data is received from a device. A destination is selected for the payload data based on a characteristic of the multiple access network. The payload data is transmitted to the selected destination.

Random phase multiple access system with meshing

Time division multiple access (TDMA) based medium access control (MAC) protocols can provide QoS with guaranteed access to the wireless channel. However, in multi-hop wireless networks, these protocols may introduce scheduling delay if, on the same path, an outbound link on a router is scheduled to transmit before an inbound link on that router. The total scheduling delay can be quite large since it accumulates at every hop on a path. This paper presents a method that finds conflict-free TDMA schedules with minimum scheduling delay. We show that the scheduling delay can be interpreted as a cost, in terms of transmission order of the links, collected over a cycle in the conflict graph. We use this observation to formulate an optimization, which finds a transmission order with the min-max delay across a set of multiple paths. The min-max delay optimization is NP-complete since the transmission order of links is a vector of binary integer variables. We devise an algorithm that finds the transmission order with the minimum delay on overlay tree topologies and use it with a modified Bellman-Ford algorithm, to find minimum delay schedules in polynomial time. The simulation results in 802.16 mesh networks confirm that the proposed algorithm can find effective min-max delay schedules.

Delay aware link scheduling for multi-hop TDMA wireless networks

Challenges and Issues in Designing Architectures and Protocols for Wireless Mesh Networks.- Architectures and Deployment Strategies for Wireless Mesh Networks.- End-to-End Design Principles for Broadband Cellular Mesh Networks.- Medium Access Control and Routing Protocols for Wireless Mesh Networks.- Channel Assignment Strategies for Wireless Mesh Networks.- Optimal Resource Allocation for Wireless Mesh Networks.- Resource Allocation and Cost in Hybrid Solar/Wind Powered WLAN Mesh Nodes.- Scheduling, Routing, and Related Cross-Layer Management through Link Activation Procedures in Wireless Mesh Networks.- Quality-Aware Routing Metrics in Wireless Mesh Networks.- Cross-layer Solutions for Traffic Forwarding in Mesh Networks.- Multiple Antenna Techniques for Wireless Mesh Networks.- Security Issues in Wireless Mesh Networks.

Wireless Mesh Networks: Architectures and Protocols

To meet the needs of wireless broadband access, the IEEE 80216 protocol for wireless metropolitan networks (WirelessMAN) has been recently standardized The medium access control (MAC) layer of the IEEE 80216 has point-to-multipoint (PMP) mode and mesh mode Previous works on the IEEE 80216 have primarily focused on the PMP mode In the mesh mode, all nodes are organized in an ad hoc fashion and use a pseudo-random function to calculate their transmission time based on the scheduling information of the two-hop neighbors In this paper, we develop a stochastic model for the distributed scheduler of the mesh mode With this model, we analyze the scheduler performance under various conditions, and the analytical results match very well with the ns-2 simulation results The analytical model developed in this paper is instrumental in optimizing the IEEE 80216 mesh mode system performance To the best of our knowledge, this work is the first one theoretically investigating the IEEE 80216 mesh mode scheduling performance

Modelling and performance analysis of the distributed scheduler in IEEE 802.16 mesh mode

To meet the needs of wireless broadband access, the IEEE 802.16 protocol for wireless metropolitan networks (WirelessMAN) has been recently standardized. The medium access control (MAC) layer of the IEEE 802.16 has point-to-multipoint (PMP) mode and mesh mode. Previous works on the IEEE 802.16 have primarily focused on the PMP mode. In the mesh mode, all nodes are organized in an ad hoc fashion and use a pseudo-random function to calculate their transmission time based on the scheduling information of the two-hop neighbors. In this paper, we develop a stochastic model for the distributed scheduler of the mesh mode. With this model, we analyze the scheduler performance under various conditions, and the analytical results match very well with the ns-2 simulation results. The analytical model developed in this paper is instrumental in optimizing the IEEE 802.16 mesh mode system performance. To the best of our knowledge, this work is the first one theoretically investigating the IEEE 802.16 mesh mode scheduling performance.

Performance Analysis of the Distributed Scheduler in IEEE 802.16 Mesh Mode

Broadband wireless access technology is developed very fast in recent years. The IEEE 802.16 and 802.11a are two broadband wireless access system standards for metropolitan and local areas respectively. The IEEE 802.11a works in the license-exempt (LE) band, and the IEEE 802.16 is designed such that it can operate in the same LE spectrum too. Although the two systems work in different environments, interference can exist under some scenario. In this paper, the coexistence issues of the two types of networks are investigated and a simple and accurate way for bit-error-ratio (BER) calculation is given. The analysis is also verified by Monte Carlo simulations. Furthermore, in our work, we also show how our research production is used to configure the coexisting IEEE 802.16 and 802.11a systems to mitigate the interference.

Wenchao Ma

Papers

Modelling and performance analysis of the distributed scheduler in IEEE 802.16 mesh mode

Performance Analysis of the Distributed Scheduler in IEEE 802.16 Mesh Mode

The IEEE 802.16 and 802.11a Coexistence in the License-Exempt Band