Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1998-05-22
2002-10-22
Hsu, Alpus H. (Department: 2665)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S347000, C370S412000, C370S442000, C370S469000
Reexamination Certificate
active
06469991
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a medium access control (MAC) protocol, known as an “on-demand multiple access fair queuing” system, for application in a wireless communications network system. In particular, the invention relates to a method for managing queue overload in time and frequency division half- and full-duplex multiple access wireless communications networks employing the “on-demand multiple access fair queuing” system.
BACKGROUND OF THE INVENTION
Wireless services, such as cellular voice and data and wireless LANs, are expected to enjoy rapid growth in the years to come. Third generation wireless networks designed to carry multimedia traffic are currently under intensive research, with the major goals being to provide seamless communications, high bandwidth availability, and guaranteed Quality of Service (QoS) without any location or mobility constraints.
FIG. 1
depicts a prior art wired network for data exchange. Shown are the three existing business entities whose equipment, working in concert, is typically utilized today to provide remote internet access through modems to user computers. User computers
2
and user modems
4
constitute end systems. The first business entity shown in
FIG. 1
is the telephone company (telco) that owns and operates the dial-up plain old telephone system (POTS) or integrated services data network (ISDN). The telco provides a transmission medium in the form a of public switched telephone network (PSTN)
6
over which bits or packets can flow between users and the other two business entities.
The second business entity shown in
FIG. 1
is the internet service provider (ISP). The ISP deploys and manages one or more points of presence (POPs)
8
in its service area, to which end users connect for network service. An ISP typically establishes a POP in each major local calling area in which the ISP expects to have subscribers. The POP
8
converts message traffic from the PSTN
6
into a digital form to be carried over intranet backbone
10
, which is either owned by the ISP or leased from an intranet backbone provider such as MCI, Inc. An ISP typically leases fractional or full T
1
or T
3
lines from the telco for connectivity to the PSTN. The POPs
8
and the ISP's media data center
14
are connected together over the intranet backbone
10
through router
12
A. The data center
14
houses the ISP's web servers, mail servers, accounting, and registration servers, enabling the ISP to provide web content, e-mail, and web hosting services to end users. Future value-added services may be added by deploying additional types of servers in the data center
14
. The ISP maintains router
12
A in order to connect to public internet backbone
20
. In the existing model for remote access, end users typically have service relationships with both their telco and their ISP, usually getting separate bills from each. End users access the ISP and, through the ISP, public internet
20
, by dialing the nearest POP and running a communication protocol known as the Internet Engineering Task Force (IETF) point-to-point (PPP) protocol.
The third business entity shown in
FIG. 1
is a private corporation which owns and operates its own private intranet
18
, accessed through router
12
B. Corporate employees may remotely access corporate network
18
(e.g., from home or while on the road) by making POTS/ISDN calls to corporate remote access server
16
and running the IETF PPP protocol. For corporate access, end users pay only for the cost of connecting to corporate remote access server
16
. The ISP is not involved. The private corporation maintains router
12
B in order to connect an end user to either corporate intranet
18
or public internet
20
.
End users currently pay the telco for both the cost of making phone calls and the cost of a phone line into their home. End users also must pay the ISP for access to the ISP's network and services. Today, internet service providers offer internet access services, web content services, e-mail services, content-hosting services, and roaming to end users. Because of low margins and lack of market segmentation based on features and price, ISPs are looking for value-added services to improve margins. In the short term, equipment vendors want to be able to offer solutions to ISPs that enable them to offer faster access, virtual private networking (the ability to use public networks securely as private networks and connect to intranets), roaming consortiums, push technologies, and specific Quality of Service. In the longer term, it is desired to offer voice over internet and mobility. ISPs will then be able to use these value-added services to escape from the low margin straitjacket. Many of these value-added services fall into the category of network services and can be offered only through the network infrastructure equipment. Other value-added services fall into the category of application services which require support from the network infrastructure, while still others do not require any support from the network infrastructure. In particular, services like faster access, virtual private networking, roaming, mobility, voice, Quality of Service, and QoS-based accounting all need enhanced network infrastructure.
Wireless communications networks have the advantage of being able to extend the reach of wired networks. However, achievable bandwidths in wireless networks frequently lag behind those available in wired networks. Wired broadband systems like asynchronous transfer mode (ATM) are capable of providing services with different QoS (e.g., constant bit rate (CBR), variable bit rate (VBR), and available bit rate (ABR)) for enhanced support of multimedia applications. It is desired to extend such services to wireless networks. Research on merging ATM and wireless networks is therefore currently underway in many institutions and research laboratories. Many fundamental issues, affecting everything from the access layer to the transport layer, are being studied. Besides use of ATM as a transmission format at the air interface of a wireless network, ATM is also being considered for the wired infrastructure of cellular systems. Such a wired ATM infrastructure would be capable of supporting multiple access air interface technologies (e.g., CDMA, TDMA, etc.).
In a wireless network that supports multimedia traffic, an efficient channel access protocol needs to be maximize the utilization of the limited wireless spectrum while still supporting the quality of service requirements of all traffic. Several well-known channel access protocols are currently used in wireless data systems, such as Slotted Aloha, PRMA, etc. Slotted Aloha is a simple protocol but, because it does not attempt to avoid or resolve collisions between data users, its theoretical capacity is just 0.37. In addition, Slotted Aloha is unsuitable for efficient transmission of variable-length packets.
Reservation-based protocols attempt to avoid and resolve collisions by dynamically reserving channel bandwidth for users needing to send packets. Typically, in such protocols a channel is divided into slots which are grouped into frames of N slots. A slot can be further subdivided into k minislots. Normally, N
1
of the slots will be used for reservation purposes while the remaining N−N
1
slots are data slots. The users that need to send packets send a reservation request packet in one of the M=N
1
*k minislots. If the reservation request packet is successful, then the user will be allocated a certain number of data slots until the user or the base station releases the reservation. If the reservation request packet is not successful, the user will use a conflict resolution method to retransmit the reservation request until it is successfully transmitted.
A multiple access protocol for hybrid fiber-coax networks has been proposed by Doshi et al. in “A Broadband Multiple Access Protocol for STM, ATM, and Variable Length Data Services on Hybrid Fiber-Coax Networks,” Bell Labs Technical Journal, Summer 1996, p
Hsu Alpus H.
Lucent Technologies - Inc.
Stevens Roberta
LandOfFree
Method for overload control in a multiple access system for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for overload control in a multiple access system for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for overload control in a multiple access system for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2991803