QPSX [1,16,21], a Queued Packet and Synchronous circuit eXchange, is a Metropolitan Area Network (MAN) proposed standard with IEEE 802.6. It is developed by QPSX Communications Pty. Ltd. and sponsored by Telecom Australia. QPSX is · a distributed broad-band, movable boundary [10] type communications switch, that provides integrated packet and circuit switching. Its capacity is dynamically alloc...

Optical code division multiple access (OCDMA) allows signal to be transmitted in an asynchronous manner, and promises high flexibility and simplicity with considerable security. OCDMA harnesses an enormous bandwidth that provides high spectral utilization and efficiency to support multiple, simultaneous active users. However, this multiple access technique also has impairments such as multiple ...

This paper presents the capability and challenge of a unified micro-cell-based network named MM-MAN (Mobile Multimedia Metropolitan Area Network) in providing multimedia communications to the fast terminals like those on vehicle-move. Micro-cellular network can offer rich radio resources due to high reusability of radio resource in space domain, and however, drags two major drawbacks for full s...

There has been keen interest in the literature recently on the IEEE wireless metropolitan area network (MAN) developed within IEEE 802.16. Through the use of flexible physical layer features and medium access control (MAC) layer mechanisms, this system can be used to deliver broadband voice and data into areas that may have a wide range of population densities, cell radii, propagation environme...

INTERNET traffic volumes are growing and require the transmission capacity of the underlying infrastructure to be continuously extended. A closer look at this infrastructure reveals that the Internet architecturally relies on a three level hierarchy consisting of backbone networks, metropolitan area networks, and local access networks. The national or international backbone networks will provid...

Decentralization and polycentric spatial structure strategies are important ways to alleviate urban disease in China. However, whether the urban spatial structure is meeting expectations is still unknown. Taking the Beijing Metropolitan Area as a case, the author adopted a non-parametric method to identify the subcenters, then an employment density model was used to analyze the spatial changes ...