Cordless accessed high-speed high-capacity local area networks

• US 4,807,222 A
• Filed: 08/25/1986
• Issued: 02/21/1989
• Est. Priority Date: 08/25/1986
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Amitay, Noach
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Chin, Wellington
• Application Number:
  US06/899,647
• Time in Patent Office: 911 Days
• Field of Search: 370/85, 370/86, 370/89, 370/95, 370/94
• US Class Current: 398/99
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

The present invention relates to a high-speed high-capacity Local Area Network (LAN) wherein each user, of a separate group of one or more of the network users, communicates cordlessly, using radio frequencies or infrared, with an assigned Regional Bus Interface Unit (RBIU) located in the proximity of the group. Each RBIU of the network interfaces with a high-speed serial or lower speed parallel bus of an open-ring network for purposes of transmitting information signals while receiving information signals via the high-speed serial network bus (es), Various communications protocols such as, for example, CSMA/CD, slotted ALOHA, etc. can be employed by the users in communicating with the associated RBIUs with high efficiency due to the short paths involved relative to the transmission frame durations used on the bus.

Claims

1. A Local Area communications network (LAN) comprising:

a communications bus (14,40) which is routed along a predetermined path within an area to be serviced by the LAN; and

a plurality of regional bus interface units (11) (RBIUs) disposed at separate selected points around the area to be serviced by the LAN, each RBIU comprising;

means (12, 27, FIG. 2-3;

12, 35, FIG.

     5) for providing cordless, low-level radiation, two-way communications between the RBIU and each user of a separate group of one or more network users assigned to, and located in, the proximity of the RBIU using a predetermined communications protocol;

transmitting means (20-22, 25-26, 28, FIGS. 2-3) for (a) forming an information signal received by the cordless transmission means from a user of the associated group of users into a separate packet of information with a predetermined format including a destination user'"'"'s address, (b) detecting when the communications bus is not currently propagating a packet of information from another RBIU of the network that would interfere with the transmission of the formed packet of information, and (c) transmitting the formed packet of information received from a user of the group assigned to the RBIU onto the communications bus in a detected free packet period; and

receiving means (30, 32-34, FIG.

     5) for (a) receiving formatted information signals propagating on the communications bus, (b) detecting from an included destination user'"'"'s address whether or not each received information signal is destined for a user of the group of users assigned to the RBIU, and (c) delivering an information signal destined for one of said network users to the cordless two-way transmission means for transmission to the destined user.

2. An LAN according to claim 1 wherein the LAN further comprises:

means for generating periodic frame marker signals for propagation along the communications bus, each frame marker signal indicating the beginning of a frame in which a formatted information signal can be transmitted.

3. An LAN according to claim 2 wherein the generating means is disposed at the head and of the communications bus.

4. An LAN according to claim 2 wherein the generating means is disposed within the RBIU nearest a head end of the communications bus.

5. An LAN according to claim 3 or 4 wherein transmitting means comprises:

means (22) for (a) detecting both a frame marker signal propagating on the communications bus and whether or not a formatted information signal occupies the remainder of a frame period, and (b) generating an output control signal whenever a formatted information signal does not occupy the remainder of a frame period;

means (25) for storing a formatted information signal to be transmitted over the communications bus and for transmitting the formatted information signal onto the bus in response to the output control signal from the detecting and generating means.

6. An LAN according to claim 2 wherein the receiving means comprises:

means (32) for detecting a frame marker signal propagating on the communications bus and for generating an output control signal whenever the frame marker signal is detected;

means (33) responsive to the output control signal from the detecting and generating means for temporarily storing information received from the communications bus in the frame period associated with the detected frame marker signal; and

means (34,

     35) responsive to the information stored in the storing means for determining from the included destination user'"'"'s address whether or not the received information signal is destined for a user of the group assigned to the RBIU, and for cordlessly transmitting each information signal destined for a user of said group to that user.

7. An LAN according to claim 1, 2, or 6 wherein the communications bus is a lightguide for propagating optical signals.

8. An LAN according to claim 1, 2 or 6 wherein the communications bus is capable of propagating electrical signals.

9. A Regional Bus Interface Unit (RBIU) for use in a Local Area Network (LAN), the RBIU comprising:

a first (S) and a second (R) input terminal and an output terminal (T);

means for providing cordless, low-level radiation, two-way transmissions of information signals between the RBIU and each user of a group of one or more users assigned to the RBIU;

transmiting means connected between the first input terminal and the output terminal and to the cordless transmission means for (a) arranging information signals received by the cordless transmission means from a user assigned to the RBIU into formatted packet information signals, (b) detecting when a formatted information signal is not received at the first input terminal during a predetermined time period, and (c) transmitting information signals received from a user of the group of one or more users assigned to the RBIU in a predetermined format including a destination user'"'"'s address to the output terminal during the detected time period; and

receiving means coupled to the second input terminal for (a) receiving formatted information signals from the second input terminal, (b) detecting from an included destination user'"'"'s address whether or not a received information signal is destined for a user of the group of one or more users assigned to the RBIU, and (c) delivering an information signal destined for a user of the group to the cordless two-way transmission means for transmission to the destined user.

10. An RBIU according to claim 9 wherein the transmitting means comprises:

means for (a) detecting both a periodic frame marker signal received at the first input terminal, which frame marker signal is disposed at the start of a frame period, and whether or not a formatted information signal is received at the first input terminal during the remainder of the frame period, and (b) for generating an output control signal whenever a formatted information signal is not received at the first input terminal during a frame period; and

means for storing a formatted information signal to be delivered to the output terminal and for transmitting the formatted information signal to the output terminal in response to the output control signal from the detecting and generating means.

11. An RBIU according to claim 9 or 10 wherein the receiving means comprises:

means for detecting a frame marker signal received at the second input terminal and for generating an output control signal whenever a frame marker signal is detected;

means responsive to the output control signal from the detecting and generating means for temporarily storing an information signal received at the second input terminal in a frame period associated with a frame marker signal; and

means responsive to the information signal stored in the storing means for determining from the included destination user'"'"'s address whether or not the received information signal is destined for a user of the group assigned to the RBIU, and for cordlessly transmitting each information signal destined for a user of the group to that user.

12. An RBIU according to claim 11 wherein the first and second input terminals are arranged to receive lightwave signals and the transmitting means is arranged to transmit lightwave signals to the output terminal.

13. An RBIU according to claim 11 wherein the first and second input terminals are arranged to receive electrical signals and the transmitting means is arranged to transmit electrical signals to the output terminal.

14. An RBIU according to claim 9 wherein the cordless transmission means provides two-way communications with the user of the group using radio frequency signals.

15. An RBIU according to claim 9 wherein the cordless transmission means provides two-way communications with the users of the group using infrared signals.