System, method and apparatus for extending distances between wired or wireless USB devices and a USB host

• US 7,334,072 B1
• Filed: 05/05/2004
• Issued: 02/19/2008
• Est. Priority Date: 09/27/2002
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Wright, David G.
• Primary Examiner(s): PHAN, RAYMOND NGAN
• Application Number:
  US10/839,817
• Time in Patent Office: 1,385 Days
• Field of Search: 710105-106, 710312-315, 710 58- 64, 710 5- 19, 710 36- 38, 710/72, 455/66.1, 455/456
• US Class Current: 710/315
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 13/4045 where the bus bridge performs an extender function
• CPC Class Codes: G06F 2213/3814 Wireless link with a computer system port

Abstract

A wireless Universal Serial Bus (USB) device enumerates one or more real or virtual hubs that support transmission of USB data over a wireless network. The number of virtual hubs presented to a USB host can be varied dynamically according to monitored characteristics of the wireless network, such as the propagation delay, Bit Error Rate, or USB configuration of the peripheral device. Another aspect of the wireless system varies a USB transmission rate according to the amount of bandwidth available on the wireless network.

Claims

1. A wireless Universal Serial Bus (USB) device comprising:

a circuit configured to present one or more virtual hubs to a USB host for conducting a wireless USB session with a USB peripheral;

the device associated with a device address and including one or more additional device addresses associated with each of the one or more virtual hubs;

wherein an allowable propagation delay between the USB host and the USB peripheral is determined in part by a number of device addresses configured in the circuit.

2. The device according to claim 1 wherein the USB circuitry varies a USB transmission rate according to an available bandwidth of a radio link used for the wireless USB session.

3. The device according to claim 1 wherein the circuit includes:

a radio transceiver for wirelessly transmitting and receiving USB signals;

a USB physical interface for connecting to the USB host;

multiple USB Serial Interface Engines (SIEs) coupled to the USB physical interface; and

control logic that configures different real or virtual hubs by establishing different USB Device Addresses (DA) for the SIEs.

4. The device according to claim 1 including a remote station including a wireless transceiver for conducting the wireless USB session, a USB interface for coupling to the USB peripheral to the wireless transceiver, and a processing subsystem for managing the conversion between wireless signals and USB data.

5. The device according to claim 3 wherein a base station includes a cable interface for alternatively conducting the USB session over an extended length cable longer than five meters.

6. A wireless Universal Serial Bus (USB) device comprising:

a circuit configured to present one or more real hubs and one or more virtual hubs to a USB host for conducting a wireless USB session with a USB peripheral, wherein the circuit automatically configures the one or more real hubs to include a variable number of the one or more virtual hubs, and wherein the one or more virtual hubs are provided as embedded functions in the one or more real hubs, each of the one or more real hubs and the one or more virtual hubs associated with a different device address.

7. The device of claim 6 wherein the circuit varies the number of virtual hubs presented to the USB host according to different characteristics of a wireless link used for conducting the wireless USB session.

8. The device of claim 7 wherein the different characteristics of the wireless link include:

a propagation delay across the wireless network;

a Bit Error Rate (BER) of the wireless network;

or

an available bandwidth of the wireless network.

9. The device of claim 7 wherein the USB circuitry varies the number of virtual hubs presented to the USB host according to propagation delay from USB circuitry connected between the USB host and the wireless network and between the USB peripheral and the wireless network.

10. A wireless Universal Serial Bus (USB) system;

comprising;

a remote station including a radio transceiver for establishing a wireless link for transporting USB data and a USB interface for coupling the USB data to a USB peripheral device, characteristics of the wireless link established by the radio transceiver effecting a number of virtual hubs appearing as connected between the USB peripheral device and a USB host, where the virtual hubs are included as embedded functions in one or more actual hubs.

11. The wireless Universal Serial Bus (USB) system according to claim 10 wherein a distance of the remote station from the USB host varies an available bandwidth of the wireless link and a USB bit rate mode is dynamically varied according to the varied available bandwidth.

12. The wireless Universal Serial Bus (USB) system according to claim 10 wherein a number of virtual hubs appearing to be connected to the USB peripheral is automatically varied according to a distance of the remote station from the USB host.

13. A wireless USB system according to claim 10 including a base station including a radio transceiver connecting to an opposite end of the wireless link and a processing subsystem for monitoring the characteristics of the wireless link.

14. A wireless USB system according to claim 13 including a cable transceiver coupled to the processing subsystem for alternatively transferring the USB data over an extended length cable of up to 180 feet in length.

15. A wireless Universal Serial Bus (USB) system;

comprising;

a remote station including a radio transceiver for establishing a wireless link for transporting USB data and a USB interface for coupling the USB data to a USB peripheral device, characteristics of the wireless link established by the radio transceiver effecting a number of actual or virtual hubs appearing as connected between the USB peripheral device and a USB host, wherein a number of virtual hubs appearing connected to the USB peripheral automatically varies according to a Bit Error Rate for the wireless link and enumerating the actual and virtual hubs.

16. A wireless Universal Serial Bus (USB) system;

comprising;

a remote station including a radio transceiver for establishing a wireless link for transporting USB data and a USB interface for coupling the USB data to a USB peripheral device, characteristics of the wireless link established by the radio transceiver effecting a number of actual or virtual hubs appearing as connected between the USB peripheral device and a USB host;

a base station including a radio transceiver connecting to an opposite end of the wireless link and a processing subsystem for monitoring the characteristics of the wireless link; and

a cable transceiver coupled to the processing subsystem for alternatively transferring the USB data over an extended length cable longer than a USB cable, wherein the cable transceiver is a low voltage, differential signal (LVDS) transceiver.

17. A method of wirelessly connecting one or more USB devices to a USB host comprising:

establishing a wireless link for communicating with the USB device;

emulating one or more virtual USB hubs in a single real hub;

configuring each of the one or more virtual USB hubs with a different device address; and

simulating the one or more virtual USB hubs as connected to the USB device to compensate for propagation delay over the wireless link.

18. The method according to claim 17 including:

periodically monitoring a Bit Error Rate (BER) for the wireless link;

signaling disconnection of one or more of the virtual hubs to the USB device when the BER decreases; and

signaling connection of one or more of the virtual hubs to the USB device when the BER increases.

19. The method according to claim 17 including:

determining an allowable propagation delay for the wireless link according to a number of configured device addresses.

20. A method of wirelessly connecting one or more USB devices to a USB host comprising:

establishing a wireless link for communicating with the USB device;

simulating one or more virtual USB hubs as connected to the USB device to compensate for propagation delay over the wireless link;

calculating an available bandwidth for the wireless link;

transferring USB data at a slow USB bit rate when the available bandwidth is below a fast USB bit rate; and

transferring USB data at a fast USB bit rate when the available bandwidth is at or above the fast USB bit rate.

21. A method of wirelessly connecting one or more USB devices to a USB host comprising:

establishing a wireless link for communicating with the USB device;

simulating one or more virtual USB hubs as connected to the USB device to compensate for propagation delay over the wireless link;

periodically monitoring a propagation delay for the wireless link;

signaling disconnection of one or more of the virtual hubs to the USB device when the monitored propagation delay decreases; and

signaling connection of one or more of the virtual hubs to the USB device when the monitored propagation delay increases.