Multiplex communications – Communication over free space – Portable address responsive receiver
Reexamination Certificate
1998-10-23
2002-11-12
Hsu, Alpus H. (Department: 2662)
Multiplex communications
Communication over free space
Portable address responsive receiver
C370S345000, C370S389000, C370S543000
Reexamination Certificate
active
06480477
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a terminal for a wireless network for a metropolitan area wherein the terminal achieves a transmission rate of multiples of 100 Mbps for an associated wireless link. More particularly, the invention relates to a wireless terminal having a number, n, of digital processing media access control units (MACs) multiplexed to a single radio framer so as to achieve a transmission rate of n times 100 Mbps.
BACKGROUND OF THE INVENTION
Computers utilized in modern office environments are typically coupled to a local area network (LAN). The LAN allow users of the computers to share common resources, such as a common printer included in the network, and allows the users to share information files, such as by including one or more file servers in the network. In addition, the users are typically able to communicate information with each other through electronic messaging. A commonly utilized type of LAN is Ethernet. Currently, a variety of products which support Ethernet are commercially available from a variety of sources. Other types of LANs are also utilized, such as token ring, fiber distributed data interface (FDDI) or asynchronous transfer mode (ATM).
LANs are often connected to a wide area network (WAN) via a telephone modem. Thus, information is communicated over the WAN via a communication link provided by a telephone service provider. These telephone links, however, are generally designed to have a bandwidth that is sufficient for voice communication. As such, the rate at which information can be communicated over these telephone links is limited. As computers and computer applications become more sophisticated, however, they tend to generate and process increasingly large amounts of data to be communicated. For example, the communication of computer graphics generally requires a large amount of bandwidth relative to voice communication. Thus, the telephone link can become a data communication bottleneck.
Business organizations and their affiliates are often spread over several sites in a metropolitan or geographical area. For example, a business organization can have a headquarters, one or more branch offices, and various other facilities. For such business organizations, LANs located at the various sites will generally need to communicate information with each other. Wireless communication links for connecting local area networks are known. For example, U.S. Pat. No. 4,876,742, entitled “Apparatus and Method for Providing a Wireless Link Between Two Area Network Systems,” and U.S. Pat. No. 5,436,902, entitled “Ethernet Extender,” each disclose a wireless communication link for connecting LANs.
Availability is a measure of the average number of errors which occur in digitally transmitted data. An availability of 99.99 percent is commonly required for radio communications. For an availability of 99.99 percent, the average error rate for digitally communicated data must be maintained below 1×10
−6
errors per bit, 99.99 percent of the time. The integrity of a wireless communication link, however, is largely dependent upon transient environmental conditions, such as precipitation. Environmental precipitation causes a severe attenuation of the transmitted signal. For example, to maintain an availability of 99.99 in the presence of environmental precipitation, the signal must be transmitted at a level that is 24 dB/km higher than otherwise. Therefore, to ensure an acceptable data error rate under all expected conditions, data is typically communicated over a wireless communication link at a relatively high power and at a relatively low rate. The amount of data required to be communicated over the wireless link, however, can vary widely over time and can vary independently of environmental conditions. In addition, wireless links, especially those operated at high power levels, can cause interference with other wireless links operating in the same geographical area. Thus, the wireless link can become a data communication bottleneck.
Therefore, a technique is needed for efficiently and cost effectively communicating data over a wireless link between Ethernet local area networks.
SUMMARY OF THE INVENTION
The invention is a method and apparatus for achieving a data transmission rate of multiples of 100 mega-bits per second (Mbps) in a terminal for a wireless metropolitan area network. In accordance with an aspect of the present invention, a method of communicating data packets in a wireless network includes steps of receiving a first data packet wherein the first data packet is received according to a first rate of data communication, receiving a second data packet wherein the second data packet is received according to a second rate of data communication and wherein the step of receiving the second data packet is performed simultaneously with the step of receiving the first data packet, time division multiplexing the first data packet and the second data packet to a radio frame, and communicating the radio frame via a wireless link wherein the radio frame is communicated at a third rate of data communication wherein the third rate of data communication is equal to at least a sum of the first rate of data communication and the second rate of data communication. The method can also include a step of buffering the first data packet prior to time division multiplexing the first data packet such that the step of buffering the first data packet synchronizes the first data packet to the radio frame. The method can also include a step of buffering the second data packet prior to providing the second data packet to the radio framer such that the step of buffering the second data packet synchronizes the second data packet to the radio frame. The first and second data packets can be received from an Ethernet local area network. The first data packet can be a 100 mega-bit per second (Mbps) Fast Ethernet data packet. The second data packet can be a 10 Mbps Ethernet data packet. The method can include steps of receiving a third data packet, and time division multiplexing the third data packet to the radio frame. The method can include a step of encrypting the first data packet prior to performing the step of time division multiplexing.
According to another aspect of the invention, a method of communicating data packets in a wireless network includes steps of receiving a first Fast Ethernet data packet into a first MAC unit wherein the first data packet is received at a rate of 100 Mbps, receiving a second Fast Ethernet data packet into a second MAC unit wherein the second data packet is received at a rate of 100 Mbps and wherein the step of receiving the second data packet is performed simultaneously with the step of receiving the first data packet, providing the first data packet and the second data packet to a radio framer according to time division multiplexing thereby forming a time division multiplexed radio frame, and communicating the time division multiplexed radio frame via a wireless link wherein the time division multiplexed radio frame is communicated at a rate of at least 200 Mbps. The first Fast Ethernet data packet can be received from an Ethernet local area network coupled to the first MAC unit. The method can include steps of receiving a third Fast Ethernet data packet into a third MAC unit wherein the third data packet is received at a rate of 100 Mbps, and providing the third data packet to the radio framer according to time division multiplexing. In which case, the time division multiplexed radio frame can be communicated at a rate of at least 300 Mbps. The method can include a step of buffering the first data packet in the first MAC unit prior to providing the first data packet to the radio framer. The step of buffering the first data packet can synchronize the first data packet to the radio frame. The method can also include a step of buffering the second data packet in the second MAC unit prior to providing the second data packet to the radio framer such that the step of buffering the second data packet synchronizes the
Huen Tat
Ngoc Tho Le
Treadaway Kirk
Browdy and Neimark , P.L.L.C.
Hsu Alpus H.
Innowave ECI Wireless Systems Ltd.
Qureshi Afsar M.
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