Telephone calls, data and other multimedia information is routed through a hybrid network which includes transfer of information across the internet. A media order entry captures complete user profile information for a user. This profile information is utilized by the system throughout the media experience for routing, billing, monitoring, reporting and other media control functions. Users can manage more aspects of a network than previously possible, and control network activities from a central site. The hybrid network also contains logic for responding to requests for quality of service and reserving the resources to provide the requested services.

System and method for providing requested quality of service in a hybrid network

An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.

Radio frequency local area network

Electrocardiogram (ECG) compression techniques are compared, and a unified view of these techniques is established. ECG data compression schemes are presented in two major groups: direct data compression and transformation methods. The direct data compression techniques are ECG differential pulse code modulation (DPCM) and entropy coding, AZTEC, Turning-point, CORTES, Fan and SAPA algorithms, peak-picking, and cycle-to-cycle compression methods. The transformation methods include Fourier, Walsh, and Karhunen-Loeve transforms. The theoretical bases behind the direct ECG data compression schemes are presented and classified into three categories: tolerance-comparison compression, DPCM, and entropy coding methods. A framework for evaluation and comparison of ECG compression schemes is presented. >

ECG data compression techniques-a unified approach

Telephone calls, data and other multimedia information is routed through a hybrid network which includes transfer of information across the internet utilizing telephony routing information and internet protocol address information. A media order entry captures complete user profile information for a user. This profile information is utilized by the system throughout the media experience for routing, billing, monitoring, reporting and other media control functions. Users can manage more aspects of a network than previously possible, and control network activities from a central site. Calling card access is provided for users and supports typical calls as well as media transfers over the hybrid network including over the internet.

System, method and article of manufacture for communications utilizing calling, plans in a hybrid network

A mathematical formulation is developed for systematic tracking of the random movement of a mobile station in a cellular environment. It incorporates mobility parameters under the most generalized conditions, so that the model can be tailored to be applicable in most cellular environments. This mobility model is used to characterize different mobility-related traffic parameters in cellular systems. These include the distribution of the cell residence time of both new and handover calls, channel holding time, and the average number of handovers. It is shown that the cell residence time can be described by the generalized gamma distribution. It is also shown that the negative exponential distribution is a good approximation for describing the channel holding time.

/pdf/user-mobility-modeling-and-characterization-of-mobility-48lyhrywlr.pdf

User mobility modeling and characterization of mobility patterns

A distributed microcellular architecture based on the IEEE 802.6 Metropolitan Area Network (MAN) is proposed, and is shown to meet anticipated personal communications service (PCS) needs. A method is presented to calculate MAN coverage in urban areas, and is used to demonstrate coverage of approximately 50 city blocks per MAN. A distributed subscriber database architecture is proposed to facilitate call setup, tracking of roamers and handoffs. To fully utilize MAN bandwidth, a quick method for the heat stations to switch on/off isochronous slots is proposed to facilitate adaptation to PCS traffic level variations. Call setup and handoff procedures are detailed. The PCS signaling overhead is calculated to be 15% of the capacity required to carry voice traffic. >

Network architecture and signaling for wireless personal communications

The IETF is currently specifying QoS on the Internet, but providing QoS at the IP layer is sub-optimal without lower layers' support. With the growing popularity and acceptance of IEEE 802.11 wireless LANs, it is essential to focus on QoS enhancement at the MAC layer of the 802.11 standard. The EDCF, proposed by the IEEE 802.11e, is a contention-based MAC protocol supporting service differentiation through different interframe spaces, contention window limits, and persistence factors for different traffic priority classes. In this paper, we propose a retransmission scheme, known as age-dependent backoff (ADB), to alleviate the delay and jitter of real-time packets by adjusting the persistence factors dynamically based on the ages of the real-time packets in the transmission queues and the lifetimes of the real-time packets. Simulation results indicate that using ADB in EDCF is efficient with low delay, jitter and drop rate for real-time traffic in a wide range of traffic loads.

Improving the QoS performance of EDCF in IEEE 802.11e wireless LANs

A distributed circuit-switched approach for supporting the deployment of high speed wireless personal communication services in urban areas through the interconnection of base stations via metropolitan area networks (MANs) is proposed. Broadband MANs minimize traffic congestion by dynamic sharing of link capacity and by serving as distributed switches for partitioning call control functions. While the DQDB protocol readily supports distributed packet-switching over the IEEE 802.6 MAN, isochronous traffic such as voice and video is best supported by circuit-switched connections. The authors present an enhanced bi-state pre-arbitrated (PA) transport mechanism, and associated call control and handoff management techniques, which enable distributed circuit-switching over the MAN. These capabilities are not currently addressed in the 802.6 standards. The bi-state PA transport mechanism facilitates statistical multiplexing of variable rate isochronous traffic sources. The network capacity is constrained by the call setup delay performance, and is analyzed by simulations. Alternative signaling architectures, involving different placements of call control network elements, are evaluated. The effects of erasure nodes, and close bus versus open bus architectures, are considered. The overlap inter-MAN call setup procedure is proposed to reduce delays. Different call handoff procedures are formulated according to the type of handoff and the resulting change in call connectivity. Most handoffs are intra-MAN, requiring simple procedures with short delays. >

Call control and traffic transport for connection-oriented high speed wireless personal communications over metropolitan area networks

A simple, cost-effective means is developed to estimate the time-invariant wireless radio channel impulse response h(t) using only the magnitude of the channel transfer function, H(jw). The Hilbert transform is used to calculate the phase of H(jw) from its magnitude. Inverse discrete Fourier transformation (IDFT) of H(jw) yields h(t). The Hilbert transform relation is applicable provided H(jw) is a minimum phase transfer function. An experimental in-building wireless channel testbed was established, for which h(t) was determined over the 1000-2500 MHz range. Both line of sight (LOS) and non-LOS transmission was investigated. Good agreement was observed between values of h(t) calculated from measured values of H(jw) and from those based only on [H(jw)] and its Hilbert transform. Even when the minimum phase condition is violated, h(t) as calculated from [H(jw)] and its Hilbert transform provides a useful lower bound on the time-spread of h(t). The measurement of [H(jw)] is easily implemented using a signal source, receiving antenna, and spectrum analyzer. A personal computer and software are required to calculate the phase of H(jw) and its IDTF. Existing frequency-domain measurement schemes utilize a vector network analyzer to measure H(jw) (magnitude and phase angle). Such equipment is expensive, subject to transmitter-receiver crosstalk, and restrictive as to the relative locations of the transmitting and receiving antenna.

Characterization of in-building UHF wireless radio communication channels using spectral energy measurements

The IEEE 802.6 metropolitan area network (MAN) has been proposed previously to provide for the distributed control of networks providing personal communications services (PCS). This paper continues investigations into voice transport on the MAN using pre-arbitrated (PA) bandwidth, and for signaling and data transport using queue arbitrated (QA) bandwidth. A new scheme for the transport of PCS voice is proposed. Capacity gains are realized with PA access by locating a gateway to the public switched telephone network (PSTN) at the head of bus (HOB) in a closed-bus MAN. Reductions in PCS signaling delays on the MAN are realized by applying the preemptive priority mechanism (PPM). In summary, improvements to the PA and QA transport mechanisms, as applied to personal communications networks (PCNs), are developed and assessed. Additionally, an architecture for a MAN-based PCN is presented in the context of the intelligent network (IN) and future migration towards ATM/B-ISDN.

https://ieeexplore.ieee.org/iel3/3816/11160/00533633.pdf

R.W. Donaldson

Papers

Network architecture and signaling for wireless personal communications

Improving the QoS performance of EDCF in IEEE 802.11e wireless LANs

Call control and traffic transport for connection-oriented high speed wireless personal communications over metropolitan area networks

Characterization of in-building UHF wireless radio communication channels using spectral energy measurements

Enhancements for integrated wireless personal communications over metropolitan area networks