Ajaz Sana

Design and performance of hybrid FSO/RF architecture for next-generation broadband wireless access networks

This paper proposes a novel Ethernet-based wired/wireless broadband access networking architecture that utilizes the existing wired trunk feeder fiber of typical PON infrastructure along with a hybrid FSO/RF reliable wireless connectivity to the end-users. By combining the benefits of both FSO and RF technologies, the proposed integrated networking solution can provide a downstream bandwidth of up to 2.5 Gbps per wavelength and 99.999% availability at a range of 1 km in all weather conditions [2]. All the previous work on hybrid FSO/RF was based on point to point, our proposed architecture is unique in the sense of providing point to multipoint access to end users and bringing all wired/wireless network in to single network, which is transparent to the users.

Enhanced dynamic bandwidth allocation in WDM-PON

WDM based passive optical network (PON) upgrades current TDM based PON at the architecture, protocol and dynamic bandwidth allocation algorithms to provide higher bandwidth in the access networks. Various Dynamic Wavelength and Bandwidth Allocation algorithms for WDM-PON have been studied. These DWBA algorithms exploit both inter-channel and intra-channel statistical multiplexing in order to achieve better performance, especially when the load on various channels is not symmetric. However, these algorithms let all ONUs share all wavelengths equally, and decouple bandwidth allocation from the wavelength assignment, which may cause bandwidth fragmentation across different wavelengths, and these algorithms further strictly limit the ONUs only to use one wavelength per allocation cycle, hence, leading to the underutilized network performance. To overcome the above limitation, we propose an enhanced dynamic wavelength and bandwidth allocation (EDBA) algorithm, which integrates wavelength assignment with bandwidth allocation process. We use extensive simulation to compare the performance of EDBA to another DWBA algorithm in 3.

Integration of PON and 4G mobile WiMAX networks to provide broadband integrated services to end users

Passive Optical Network (PON) and Mobile Worldwide Interoperability for Microwave Access (WiMAX) are two emerging broadband technologies for the next-generation (NG) access networks. Integration of PON and Mobile WiMAX might be an efficient solution to broadband network access that can take advantage of the bandwidth benefit of fiber communications, and the mobile and non-line-of-sight features of wireless communications. By leveraging the advantages of both of these access technologies combined on an integrated architecture platform, NG converged-access solutions can meet the demand for mobility, bandwidth, reliability, security, and flexibility. By combining the practically unlimited capacity of optical fiber networks with the ubiquity and mobility of wireless networks, NG Fiber-Wireless (FiWi) networks will enable the support of a wide range of emerging and unforeseen fixed-mobile applications and services independent of the access infrastructure. PON and 4G Mobile WiMAX integrated architecture enables differentiated bandwidth allocation to end users that can provide more network capacity at reduced operational cost as compared to other existing technologies.

Introduction and comparison of next-generation mobile wireless technologies

Mobile networks and services have gone further than voice-only communication services and are rapidly developing towards data-centric services. Emerging mobile data services are expected to see the same explosive growth in demand that Internet and wireless voice services have seen in recent years. To support such a rapid increase in traffic, active users, and advanced multimedia services implied by this growth rate along with the diverse quality of service (QoS) and rate requirements set by these services, mobile operator need to rapidly transition to a simple and cost-effective, flat, all IP-network. This has accelerated the development and deployment of new wireless broadband access technologies including fourth-generation (4G) mobile WiMAX and cellular Long-Term Evolution (LTE). Mobile WiMAX and LTE are two different (but not necessarily competing) technologies that will eventually be used to achieve data speeds of up to 100 Mbps. Speeds that are fast enough to potentially replace wired broadband connections with wireless. This paper introduces both of these next generation technologies and then compares them in the end.

A Novel PON Based Mobile Distributed Cluster of Antennas Approach to Provide Impartial and Broadband Services to End Users

In this research paper we propose a novel Passive Optical Network (PON) based Mobile Worldwide Interoperability for Microwave Access (WiMAX) access network architecture to provide high capacity and performance multimedia services to mobile WiMAX users. Passive Optical Networks (PON) networks do not require powered equipment; hence they cost lower and need less network management. WiMAX technology emerges as a viable candidate for the last mile solution. In the conventional WiMAX access networks, the base stations and Multiple Input Multiple Output (MIMO) antennas are connected by point to point lines. Ideally in theory, the Maximum WiMAX bandwidth is assumed to be 70 Mbit/s over 31 miles. In reality, WiMAX can only provide one or the other as when operating over maximum range, bit error rate increases and therefore it is required to use lower bit rate. Lowering the range allows a device to operate at higher bit rates. Our focus in this research paper is to increase both range and bit rate by utilizing distributed cluster of MIMO antennas connected to WiMAX base stations with PON based topologies. A novel quality of service (QoS) algorithm is also proposed to provide admission control and scheduling to serve classified traffic. The proposed architecture presents flexible and scalable system design with different performance requirements and complexity.

A novel fair queuing algorithm for hybrid wired/wireless architecture with wireless compensation to provide end-to-end quality of service support

We proposed novel hybrid FSO/RF architecture1 to provide broadband wireless access to end users. To provide quality of service (QoS) bounds for different types of traffic(voice, video and data) we proposed some fair queuing algorithms2,3 ,but because of the hybrid wired and wireless links there can be certain times allocated to a host when that host is unable to transmit data because of wireless link errors. These wireless link errors are location dependent and bursty. The channel errors can occur from multi-path fading, shadow fading or interference from another device. In this paper we proposed a novel fair queuing algorithm to provide end to end QoS bounds to the end users for the proposed architecture .The algorithm provide QoS bounds for Ethernet traffic in the wired domain as well as in wireless domain with compensation for wireless link errors. Scheduler maps priorities and weights for QoS of the Ethernet traffic into wireless MAC. By supporting existing Ethernet traffic QoS parameters 4-7, scheduler avoids the need to redefine QoS parameters for wireless channel. By simulations and analysis we proved that the algorithm guarantees (1) delay and throughput for error-free flows, (2) short term fairness among error-free flows, (3) long term fairness among errored and error-free flows,(4) graceful degradation for leading flows and graceful compensation for lagging flows. Each connection QoS is guaranteed by calculating bounds on delay and reserving the Bandwidth (BW).

A novel PON based UMTS broadband wireless access network architecture with an algorithm to guarantee end to end QoS

In this paper we proposes a novel Passive Optical Network (PON) based broadband wireless access network architecture to provide multimedia services (video telephony, video streaming, mobile TV, mobile emails etc) to mobile users. In the conventional wireless access networks, the base stations (Node B) and Radio Network Controllers (RNC) are connected by point to point T1/E1 lines (Iub interface). The T1/E1 lines are expensive and add up to operating costs. Also the resources (transceivers and T1/E1) are designed for peak hours traffic, so most of the time the dedicated resources are idle and wasted. Further more the T1/E1 lines are not capable of supporting bandwidth (BW) required by next generation wireless multimedia services proposed by High Speed Packet Access (HSPA, Rel.5) for Universal Mobile Telecommunications System (UMTS) and Evolution Data only (EV-DO) for Code Division Multiple Access 2000 (CDMA2000). The proposed PON based back haul can provide Giga bit data rates and Iub interface can be dynamically shared by Node Bs. The BW is dynamically allocated and the unused BW from lightly loaded Node Bs is assigned to heavily loaded Node Bs. We also propose a novel algorithm to provide end to end Quality of Service (QoS) (between RNC and user equipment).The algorithm provides QoS bounds in the wired domain as well as in wireless domain with compensation for wireless link errors. Because of the air interface there can be certain times when the user equipment (UE) is unable to communicate with Node B (usually referred to as link error). Since the link errors are bursty and location dependent. For a proposed approach, the scheduler at the Node B maps priorities and weights for QoS into wireless MAC. The compensations for errored links is provided by the swapping of services between the active users and the user data is divided into flows, with flows allowed to lag or lead. The algorithm guarantees (1)delay and throughput for error-free flows,(2)short term fairness among error-free flows,(3)long term fairness among errored and error-free flows,(4)graceful degradation for leading flows and graceful compensation for lagging flows.

A Novel Fair Queuing Algorithm for Hybrid Wired/Wireless Quality of Service Support with Wireless Compensation

This paper proposes a novel fair queuing algorithm for hybrid wired and wireless access network with wireless compensation to provide QoS bounds to Ethernet traffic. Scheduler maps priorities and weights for QoS of the Ethernet into wireless MAC. The Ethernet traffic is divided in to three flows [1-4], each flow has different requirement for loss and delay. By supporting existing Ethernet traffic, scheduler avoids the need to redefine QoS parameters for wireless channel. Real time traffic uses fair-queuing model, non real time data use weighted round robin with re-circulating queue to accommodate wireless link error. Best effort traffic use FIFO mechanism. The algorithm is adjusted for wireless link failures which are location dependent and bursty.

A Novel Ethernet-Based Wired/Wireless Broadband Access Network

This paper proposes a novel Ethernet-based wired/wireless broadband access networking architecture that utilizes the existing wired trunk feeder fiber of typical PON (passive optical networks) infrastructure along with a hybrid FSO/RF (HFR), reliable wireless connectivity to the end users. The proposed architecture reduces the cost drastically as compare to conventional PON and provides 99.999% availability at range of 1 km in all weather conditions (S. Bloom, et al., 2002). Most of the previous work on HFR has only considered point to point communication links, where the main objective was to increase maximum distance covered by HFR link (G. Clark, et al., 2001), (E. J. Korewar, Nov. 1998), (P. F. Szajowski, et al., 1999). The proposed architecture is point to multipoint HFR networking architecture and to the best of our knowledge, is the first work that considers HFR in a networking environment to provide broadband access to the end-users. This is extension of our previous work (S. Ajaz, et al., 2006) to provide QoS (quality of service) to end users