WO2001031459A9

WO2001031459A9 - Wireless universal serial bus system

Info

Publication number: WO2001031459A9
Application number: PCT/US2000/029292
Authority: WO
Inventors: Brian D Brown; Jeffrey S Ernst; Robert J Fisher; Steven L Iezzi; Susan Q Kawa; David Squires
Original assignee: Aerwire Corp
Priority date: 1999-10-22
Filing date: 2000-10-23
Publication date: 2002-07-04
Also published as: WO2001031459B1; WO2001031459A1; AU2248001A

Abstract

A system for communicating data signals between a computer processor (80) and a peripheral device (22) includes a controller device (14) associated with the computer processor; a proxy device (16) coupled to the controller device; and a peripheral device (22) coupled to the proxy device. The proxy device is adapted for receiving a first data signal transmitted from one of the controller device and the peripheral device, and transmitting the first data signal to the other of the controller device and the peripheral device, while instructing the one of the controller device and peripheral device to resend the first data signal; and receiving a second data signal from the other of the controller device and the peripheral device and transmitting the second data signal to the one of the controller device and the peripheral device in response to first data signal resent by the one of the controller device and the peripheral device.

Description

WIRELESS UNIVERSAL SERIAL BUS SYSTEM

Field of the Invention

The present invention relates generally to a wireless universal serial bus (USB) system and more particularly to a USB system including a proxy device that transmits communications over a wireless communication path between a USB host controller and a peripheral USB device in a manner that is transparent to both the USB host controller and the USB peripheral device.

Background of the Invention

A Universal Serial Bus (USB) system provides a stable and standardized way to connect up to 127 peripheral devices to a computer. Typical USB peripheral devices include printers, scanners, mice, joysticks, speakers and storage devices. USB peripheral devices are "hot" connectable and disconnectable, meaning that a USB device can be connected to and/or disconnected from the computer without having to restart the computer. When a peripheral device is connected to a computer, the operating system automatically detects and enumerates the device. By enumerating the device, the host controller associated with the operating system assigns the device an address and determines what type of data transfer the device will perform. Data transfer types include interrupt transfers, control transfers; bulk transfers and isochronous transfers. Interrupt transfers are performed by a device such as a mouse or keyboard which sends small amounts of data to the host controller; control transfer are used to send control signals between devices; bulk transfers are performed by, for example, a printer which receives data in one large packet; and isochronous transfers are performed by streaming devices such as speakers, in which data streams between the device and the host controller in real time with no error correction. Based on the transfer type and address assigned to each device, the host controller is able to more effectively communicate with the peripheral device than in non-USB systems. However, due to timing constraints associated with the USB protocol, the length of the cable that connects the peripheral device to the computer is limited, thus requiring that all of the peripheral devices connected to the computer be located within a fixed range of the computer. Furthermore, the cables associated with a large number of peripheral USB devices can cause safety hazards and can be difficult to manage and route between the devices.

Summary of the Invention

The present invention is directed to a USB system which includes an upstream hub which is connected to the host controller and a downstream hub which is connected to one or more USB peripheral devices. Communication between the upstream and downstream hubs is carried out over a wireless communication path, such as a radio frequency (RF) or infrared (IR) path.

According to one aspect of the invention, a system for communicating data signals between a computer processor and a peripheral device includes a controller device associated with the computer processor; a proxy device coupled to the controller device; and a peripheral device coupled to the proxy device. The proxy device is adapted for:

A. receiving a first data signal transmitted from one of the controller device and the peripheral device, and transmitting the first data signal to the other of the controller device and the peripheral device while instructing the one of the controller device and peripheral device to resend the first data signal; and B. receiving a second data signal from the other of the controller device and the peripheral device and transmitting the second data signal to the one of the controller device and the peripheral device in response to first data signal resent by the one of the controller device and the peripheral device.

The proxy device may include an upstream device coupled to the controller device and a downstream device coupled to the peripheral device, the upstream and downstream devices being couplable to each other by a communication path for transmitting the first and second data signals between the controller device and the peripheral device. The communication path may be a wireless path which may be one of a radio frequency path and an infrared path. The controller device may be a universal serial bus controller and the peripheral device may be a universal serial bus peripheral device. According to another embodiment of the invention, a method of communicating data signals between a computer processor and a peripheral device includes:

A. transmitting a first data signal from a controller device associated with the computer processor to a proxy device;

B. transmitting the first data signal from the proxy device to the peripheral device;

C. transmitting a request from the proxy device to the controller device to resend the first data signal; D. transmitting a second data signal from the peripheral device to the proxy device;

E. retransmitting the first data signal from the controller device to the proxy device; and

F. transmitting the second data signal from the proxy device to the controller device in response to the retransmitted first data signal.

Step B may include transmitting the control data signal from an upstream element of the proxy device to a downstream element of the proxy device and then transmitting the first data signal from the downstream element to the peripheral device. Step C may be performed by the upstream element. Step F may include transmitting the second data signal from the downstream element of the proxy device to the upstream element of the proxy device and then transmitting the second data signal from the upstream element to the controller device. The first data signal and the second data signal may be transmitted between the upstream element and the downstream element over a wireless communication path, which may be one of a radio frequency path and an infrared path.

According to yet another embodiment of the invention, a universal serial bus communication system includes a first hub device having a first port adapted for receiving and transmitting data signals in a USB format from and to an upstream device, a second port adapted for transmitting and receiving data signals in a wireless format, and a data signal conversion device adapted for converting the data signals in the USB format to the data signals in the wireless format and for converting the data signals in the wireless format to the data signals in the USB format; and a second hub device having a first port adapted for receiving and transmitting data signals in the wireless format from and to the second port of the first hub device, a second port adapted for receiving and transmitting data signals in the USB format from and to a downstream device, and a data signal conversion device adapted for converting the data signals in the USB format to the data signals in the wireless format and for converting the data signals in the wireless format to the data signals in the USB format.

Brief Description Of The Drawings The foregoing and other objects of this invention, the various features thereof, as well as the invention itself may be more fully understood from the following description when read together with the accompanying drawings in which:

Fig. 1 is a schematic diagram of the wireless USB system of the present invention; Fig. 2 is a flow diagram showing the method of transmitting data signals downstream in accordance with the present invention;

Fig. 3 is a flow diagram showing the method of transmitting data signals upstream in accordance with the present invention;

Fig. 4 is a more detailed schematic diagram of the wireless USB system in accordance with the present invention;

Fig. 5 is a more detailed schematic diagram of an alternative embodiment of the wireless USB system in accordance with the present invention;

Fig. 6 is a detailed block diagram of the upstream hub of the present invention; and Fig. 7 is a detailed block diagram of the downstream hub of the present invention.

Detailed Description Of The Preferred Embodiments

Referring now to Fig. 1, the wireless USB system 10 of the present invention will be described. System 10 includes a personal computer (PC) 12 which includes a USB host controller 14, a USB proxy hub 16 which includes an upstream hub 18 and a downstream hub 20 and a USB peripheral device 22. As shown in Fig. 1 , host controller 14 is connected to the upstream hub 18 with a conventional USB cable 24 and downstream hub 20 is connected to the USB peripheral device with a conventional USB cable 26. As described in greater detail below, upstream hub 18 is connected to downstream hub 20 via a wireless connection path 28, which preferably is an RF communication path, but may be IR or any other compatible wireless technology. Communication over the wireless path 28 may be in the USB protocol, or in any suitable communication protocol.

Host controller 14 provides and manages access to the USB system. It performs several functions, such as managing the states of attached USB peripheral devices, converting protocol and data between native format and USB standard protocol, generating frames according to the protocol, processing data transmission requests and handling transmission errors. The USB protocol requires, among other things, that a round-trip response time delay for transmission between the host controller and the peripheral device be within a specified time. This allows the USB system to maintain its high data rate and to support devices with real-time requirements. As a result of this, if the host controller does not receive an expected response within the specified time, it will invalidate the transaction. Since, due to the increased processing time of wireless transmission, the wireless transmission of the data signals in the present invention can violate the maximum round-trip transmission time requirement, a retransmission scheme is implemented in order to prevent the invalidation of valid transactions.

In the wireless USB system of the present invention, the proxy hub 16 transfers data signals between the host controller 14 and the peripheral device 22 in a transparent manner such that the host controller 14 and the peripheral device 22 "think" that they are communicating directly with each other. This is carried out by the use of so-called "NAK" packets which are transmitted to the host controller 14 and the peripheral device 22 by the upstream hub 18 and the downstream hub 20, respectively. As described above, under the USB protocol, a first device requesting a response from a second device must receive the response within a predefined time frame. If the response is not received within the predefined time frame, the first device assumes that the second device is disabled or otherwise unavailable. However, the second device can send a NAK packet to the first device to instruct the first device to resend the request thereby giving the second device more time to respond. These NAK packets are transmitted by the upstream hub 18 and to the host controller 14 in order to obtain more time to transmit the request to the downstream hub and then to the peripheral device, and then for the peripheral device to transmit its response through the downstream hub and the upstream hub to the host controller. Since the transmission of the request from the upstream hub through the downstream hub to the peripheral device and the subsequent transmission of the response from the peripheral device through the downstream hub to the upstream hub typically takes longer than the convention USB protocol timeout, NAK packets are transmitted from the upstream hub to the host controller during the transmission so that the host controller does not conclude that the peripheral device is unavailable. Likewise, the downstream hub transmits NAK packets to the peripheral device during an upstream transmission.

Fig. 2 is a flow diagram that shows the method of transmitting a control data signal from the host controller to the peripheral device and transmitting a response data signal from the peripheral device to the host controller. In step 30, host controller 14 transmits a control data signal to the peripheral device 22. This control data signal can be transmitted by the host controller for a number of reasons, such as to check the status of the peripheral device or to instruct the peripheral device that the host controller will be sending data to the peripheral device. At this point, the host controller is not aware that the proxy hub is connected between it and the peripheral device. In step 32, the upstream hub receives the control data signal from host controller 14 on connection 24 and transmits the control data signal to the downstream hub 20 over the wireless connection path 28, step 34. Concurrently, upstream hub 18 transmits a NAK packet to the host controller 14 over connection 24, step 36. This NAK packet will instruct the host controller to resend the control data signal. From the point of view of the host controller, the NAK packet was received from the peripheral device, which is typical in the USB protocol. During the transmission of the NAK packet to the host controller and the resulting retransmission of the control data signal from the host controller to the upstream device, the transmission of the original control data signal to the peripheral device and the transmission of a response data signal from the peripheral device to the upstream device is carried out. In step 38, the downstream hub 20 transmits the control data signal to the peripheral device which, in response to the control data signal, transmits a response data signal , step 40. From the point of view of the peripheral device, it is transmitting the response data signal directly to the host controller 14, which is typical in the USB protocol. The downstream hub 20 receives the response data signal from the peripheral device 22 over connection 26 and transmits the response data signal to the upstream hub 18 over the wireless connection path 28, step 42. When the upstream hub 14 receives the response data signal, step 44, it attaches a time tag to the response data signal in order to keep track of the order of received response data signals, step 46. The upstream hub 18 stores the response data signal in memory until it receives the control data signal retransmitted from the host controller in response to the NAK packet, step 48. Upon receiving the retransmitted control data signal from the host controller 14, the upstream device searches its memory for the most recent response data signal that was transmitted from the peripheral device 22 in response to the control data signal transmitted thereto by the host controller 14, step 50. The upstream hub 18 then transmits the appropriate response data signal to the host controller 14 over connection 24, step 52.

As stated above, the proxy hub 16 is effectively transparent to both the host controller 14 and the peripheral device 22. If, due to the distance between the upstream hub 18 and the peripheral device 22, the transmission of the original control data signal from the upstream hub 18 to the peripheral device 22 takes longer than the typical USB protocol timeout, in which case the host controller would assume that the peripheral device was unavailable, the upstream device 18 continues to transmit NAK packets to the host controller 14 until the upstream hub 18 receives the response data signal from the peripheral device 22 through the downstream hub 20. This causes the host controller to continue retransmitting the control data signal to what it thinks is the peripheral device 22. This NAK packet retransmission scheme forces the host controller 14 to wait for the response data signal to be received without timing out. As set forth above, from the point of view of the host controller, the NAK packets are being sent directly from the peripheral device 22.

Fig. 3 is a flow chart which shows the method of transmitting a configuration data signal from the peripheral device 22 to the host controller 14 and transmitting a response data signal from the host controller 14 to the peripheral device 22. In step 54, peripheral device 22 transmits a configuration data signal to the host controller 14. This configuration data signal can be transmitted from the peripheral device 22 to the host controller for a number of functions, such as to inform the host controller 14 of the configuration specifications of the peripheral device or to instruct the host controller that the peripheral device will be transmitting data to the host controller. In step 56, the downstream hub 20 receives the configuration data signal over connection 26 and transmits the configuration data signal to the upstream hub 18 over the wireless communication path 28, step 58. Concurrently, downstream hub 20 transmits a NAK packet to the peripheral device 22, step 60, which instructs the peripheral device 22 to retransmit the configuration data signal. From the point of view of the peripheral device, the NAK packet is received from the host controller 14, which is typical in the USB protocol. During the transmission of the NAK packet to the peripheral device 22 and the resulting retransmission of the configuration data signal from the peripheral device 22 to the downstream device, the transmission of the original configuration data signal to the host controller and the transmission of a response data signal from the host controller to the downstream device is carried out. In step 62, the upstream hub 18 transmits the configuration data signal to the host controller which, in response to the configuration data signal, transmits a response data signal to the upstream hub over connection 24, step 64. From the point of view of the host controller 14, it is transmitting the response data signal directly to the peripheral device, which is typical in the USB protocol. The upstream hub 18 transmits the response data signal to the downstream hub 20 over the wireless connection path 28, step 66. After the downstream hub 20 receives the response data signal, step 68, it stores the response data signal in memory. Upon receiving the configuration data signal retransmitted from the peripheral device 22, step 70, the downstream hub 20 transmits the appropriate response data signal stored in its memory to the peripheral device 22, step 72.

Again, as stated above, the proxy hub 16 is effectively transparent to both the host controller 14 and the peripheral device 22. If, due to the distance between the downstream hub 20 and the host controller 14, the transmission of the original configuration data signal from the downstream hub 20 to the host controller 14 takes longer than the typical USB protocol timeout, in which case the peripheral device would assume that the host controller was unavailable, the downstream device 20 continues to transmit NAK packets to the peripheral device 22 until the downstream hub 20 receives the response data signal from the host controller 14 through the upstream hub 18. This causes the peripheral device 22 to continue retransmitting the configuration data signal to what it thinks is the host controller 14. This NAK packet retransmission scheme forces the peripheral device 22 to wait for the response data signal to be received without timing out. As set forth above, from the point of view of the peripheral device 22, the NAK packets are being sent directly from the host controller 14.

Fig. 4 is a more detailed block diagram of the wireless USB system 10 of Fig. 1. As shown in Fig. 4, the personal computer 12 includes, in addition to host controller 14, a computer processor 80 and bus architecture 82. Proxy hub 16 includes multiple upstream hubs 18 which are connected to multiple downstream hubs 20, each being connected to a peripheral device 22. Each upstream hub 18 is a cascadable hub, in which further upstream hubs may be connected to the downstream side of the preceding upstream hub, as shown in the figure. This enables the system 10 to support up to 127 peripheral devices 22 which are connected to the upstream hubs 18 through respective downstream hubs 20. While in the preferred embodiment of the invention, the upstream hubs 18 are connected to the downstream hubs 20 by a wireless connection, it will be understood that they can also be connected by a wired connection while still utilizing the method of communicating therebetween, as described above. Alternatively, as shown in Fig. 5, the system 10 could include a PC 12 having an upstream hub 18a located within the PC 12 and an antenna 84 which is connected to the upstream hub 18a. Antenna 84 receives downstream data signals from the upstream hub 18a and transmits them to a further upstream hub 18b, as well as downstream hubs 20, which transmit the data signals to the respective peripheral devices 22. Likewise, antenna 84 receives upstream data signals from downstream hubs 20 and upstream hub 18b and transmits them to upstream hub 18a. Fig. 6 is a block diagram showing the components that make up the upstream hub 18. Upstream hub 18 includes a USB protocol engine 100, which includes a serial interface engine (SIE) 102, device/endpoint control logic 104, RAM access arbiter 106, Packet MMU logic device 108 and USB transceiver 110 for transmitting and receiving USB signals to the host controller 14 over connection 24. An antenna device 1 12 is connected to a transceiver 114 for transmitting and receiving data signals to and from the downstream hub. A base band processor 116 processes the outgoing USB signals into a form that is capable of being transmitted in an RF format and converts the RF signals received back into the USB format. Media access control interface 116 is used for identifying the origin of the signals processed by the upstream hub and control processor 120 controls the operation of the upstream hub 18. General purpose RAM 122 is used for storing device descriptors for the USB system, FLASH ROM 124 is used for storing operating code for the upstream hub 18, and FIFO RAM 126 is a buffer memory for storing transmission and reception address data for each transaction. Device/endpoint logic device 128 is used in conjunction with the RAM access arbiter for processing address data associated with the USB transactions. Upstream hub 18 also includes an IrD A/serial interface 130 which is used for configuring downstream components into the system, as is described in greater detail below.

USB protocol engine 100 handles arbitrary USB device addresses, endpoints and directions. The basic scheme uses a 4096 byte lookup table in dual-ported RAM that can be written to and read from by both the PC 12 and the protocol engine 100. Lookup table values are accessed using a 12-bit index (A0 through Al 1) comprised of the following fields taken from the USB transaction:

In practice, this lookup table is initially filled with a value that denotes "invalid/unconfigured", such as a value having an invalid FIFO field. Then, as the peripheral devices are configured, the appropriate lookup table entries are filled in with the FIFO number to which data is written or from which data is read. The hardware design uses a FIFO address for each endpoint to be supported. Such a design, for example, allocates 8 input FIFOs and 8 output FIFOs to be shared across all device addresses. PC 12 manages the allocation of input and output FIFOs.

Conventionally, the DIR bit sense is zero for an input to the host controller and a one for an output from the host controller. Extra bits in each lookup table entry contain additional information such as whether the transaction requires handshakes/retries or not. Conventionally, isochronous transfers do not require handshakes. Thus, an example entry in the lookup table looks like the following, where the ISOC bit indicates that handshakes and retries should not be performed on these transactions:

Only FIFO numbers corresponding to input FIFOs appear in the first half of the lookup table. Similarly, the second half of the lookup table is reserved for output FIFO numbers.

Once the lookup table is configured by the PC 12, protocol engine 100 uses the lookup table as follows. When a token is issued by the host controller 14 where the data direction, PID is 0x01 (OUT), OxOd(SETUP) or 0x09(IN), the protocol engine 100 generates an index into the lookup table based upon the data direction, the USB address and endpoint number. The protocol engine 100 then fetches the corresponding value from the lookup table RAM. If the fetched value indicates that the address/endpoint/direction is not configured, then the appropriate USB protocol action can be taken. If the value fetched from the FIFO is a valid FIFO number, the protocol engine determines from the state of the DIR bit whether it should be setting up to write to an output FIFO or to read from an input FIFO. The ISOC bit tells the protocol engine whether handshaking is required for transactions involving this address/endpoint/direction. The empty status of the specified FIFO is used to determine whether or not to generate a NAK response to the host controller 14. This empty status is also able to be used to cause an interrupt to inform the PC 12 that data is needed for that particular address/endpoint/direction. These NAK indications are posted to a status FIFO before generating an interrupt so that the PC 12 can handle multiple N AKs per interrupt.

Fig. 7 is a block diagram showing the components that make up the downstream hub 20. Downstream hub 20 includes an antenna 140 which is connected to transceiver 142 for transmitting and receiving data signal to and from the upstream hub 18. Similar to upstream hub 18, downstream hub 20 includes a base band processor 144 for converting data signals from USB format to RF format and vice versa, a MAC interface 146 and a control processor 148 for controlling the operation of the downstream hub 20. A host controller 150 is included, which may be any type of embedded host controller such as OHCI or UHCI, and RAM 152 is used for storing device descriptors for the USB system and FLASH ROM 154 is used for storing operating code for the downstream hub 20. Hub logic device 156 controls the transmission and reception of USB data signals from peripheral device over connection 26. Downstream hub 20 includes a serial interface 158 which is used in conjunction with the IrD A/serial interface 130 of upstream device 18 for configuring the downstream hub 20 into the system 10, as is discussed in greater detail below.

The configuration of upstream hub 18 and downstream hub 20 into the system 10 is as follows. After the upstream hub 18 is connected to host controller 14 by connection 24, host controller 14 detects that a full speed USB device has been attached. The host controller 14 then issues a USB reset signal to the upstream hub, which causes the upstream hub 18 to clear its internal configuration tables of all USB information. Upstream hub 18 creates a single hub object to manage all communicating downstream hubs and programs its USB device address to the default address (0). Host controller 14 issues a GET_DESCRIPTOR command to USB address 0 (the default address), endpoint 0. Upstream hub 18 responds by identifying itself as a standard USB hub class device, and provides the necessary USB information to the host controller, such as vendor identification and maximum packet size for endpoint 0 of the upstream hub 18. Host controller 14 issues a SET_ADDRESS command to address 0, endpoint 0. This data packet contains the USB address "X" assigned to the upstream hub 18. Upstream hub 18 receives the SET_ADDRESS data packet and reprograms its protocol engine 100 to recognize the device address specified in the SET_ADDRESS command. Host controller 18 then sends a device request to upstream hub address "X" and the upstream hub 18 responds with "canned" information about itself. Host controller 14 sends a configuration request to upstream hub address "X" to retrieve the single configuration supported by the upstream hub 18. Upstream hub 18 responds with canned information about the configuration that it supports, including a configuration descriptor, an interface descriptor and an endpoint descriptor. The endpoint descriptor that is returned is a status change endpoint descriptor. Host controller 18 then sends a SET CONFIGURATION command to address "X" to select a particular configuration to use. Upstream hub 18 then configures its protocol engine 100 to use the requested configuration. At this point, host controller 14 considers upstream hub 18 functional and can start issuing port control commands and start polling the upstream hub 18 for hub port status changes.

When the upstream hub 18 is configured, the downstream hub 20 can be configured into the system 10. This is done by placing the IrDA interface 130 of upstream device 18 within approximately one meter of the serial interface 158 of downstream hub 20. Power is applied to downstream device 20 and a configuration process is initiated between the IrDA interface of the upstream hub 18 and the serial interface 158 of the downstream hub 20. In order to configure peripheral devices 22 with the downstream hub 20, the hub is powered up and initialized. All downstream USB ports of the downstream hub 20 are set to a disabled state. When a peripheral device 22 is plugged into a USB port of the downstream hub 20. At this point, when OHCI host controller 150 detects the attached peripheral device 22, the new status is recorded in one of two port status registers in the OHCI host controller 150. The presence of an attached peripheral device 22 is detected via a polling process carried out by the downstream hub 20. When an attached peripheral device is detected, downstream hub 20 sends a status change message to the upstream hub 18. This status change message includes the downstream hub unit number, the USB port number and status change information included in Table 1 below.

TABLE 1

When the USB port status change message is received by upstream hub 18, it is decoded and used to update port status tables. Any change in status is flagged and the new status is incorporated into the status tables. Host controller 14 periodically polls upstream hub 18 for its status using an INT transaction that is responded to by upstream hub 18 with a data packet if a status change has occurred or a NAK if no change has occurred. The data packet contains bit fields identifying the port that has changed. Host controller 14 then sends a GET_STATUS command to the upstream hub 18 address "X" asking for the complete status for the port that changed. Upstream hub 18 responds to the host controller 14 with information in its hub status tables that is in the form of two 16 bit words. The first word is the port status and the second word is a port change mask. The port change mask indicates which bit positions in the port status word have changed. The bit assignments for the port status word are shown in Table 1.

Upstream hub 18 posts the two 16-bit words of response data to its protocol engine 100 endpoint 0 buffer so that they are available to the host controller 14 as the response to the GET STATUS command. When the host controller 14 interprets the port status word and the port change mask word, it recognizes that a peripheral device 22 has been added to the system. From this information, it also determines whether the peripheral device is a full speed or low speed USB device. Host controller 14 then resets and enables the USB port ofthe downsfream hub 20 that has changed. This is done by means of a SET FEATURE command to the upstream hub 18 address "X" on the default endpoint (0). The format of the SET_FEATURE command is as follows:

When upstream hub 18 receives this command, it sends an acknowledge signal to the host controller 14. The command is then decoded by the protocol engine 100 and, when it is recognized as a hub control command, it is sent to the downstream hub 20 that includes the changed port. When the downstream hub 18 receives the command, it generates a request to its OHCI host controller 156 to reset the indicated port. Once the reset is complete, the port is enabled.

Once the port is enabled, the downstream hub 20, during its periodic polling procedure, recognizes the change in the USB port status for the port that has been enabled. Table 2 shows the UHCI controller port status/control register.

TABLE 2

Table 2 (cont'd)

When downstream hub 20 sees that bit 3 has gone high (1), it recognizes the status change of the port. Downstream hub 20 sends a status change message to upstream hub 18 which includes an identification number of the downstream hub 20, an identification number of the USB port that has had a status change and all of the status change information shown in Table 1, above. Upstream hub 18 decodes the USB port status message and updates its port status tables. Any change in status of the ports is flagged and the new status is incorporated into its status tables. When host controller 14 next polls upstream hub 18 for status, upstream hub 18 reports the change in status. Host controller 14 then begins the enumeration process on the newly attached peripheral device 22 by issuing a GETJDESCRIPTOR command to upstream hub 18. The command is a SETUP- DAT A0 transfer from the host controller 14 followed by an IN-DATA1 transfer, in which the addressed peripheral device is expected to send the DATA1 packet back to host controller 14. When upstream hub 18 receives the command, the SETUP- DAT A0 packet is acknowledged. However, because the protocol engine 100 has no data queued to send on endpoint 0 for peripheral device address 0, the IN data stage transfer is N AKed. Upstream hub 18 checks its emulated hub state and confirms that the system is configured and therefore no longer responds to address 0. It then checks to see which of its hub ports was last reset and identifies on which downstream hub 20 that port resides. Upstream hub 18 then sends the GET_DESCRIPTOR command from host controller 14 to the appropriate downstream hub 20. Alternatively, a peripheral device can be connected to a downstream hub 20 using its standard USB connection 26, taking advantage of the "hot connect" feature of the standard USB protocol. Communication between the peripheral device 22 and downstream hub 20 is standard USB communication. Downstream hub 20 communicates with peripheral device 22 in such a way that it convinces peripheral device 22 that it is the host controller 14. This enables it to receive specific data regarding the communication requirements of the peripheral device 22. Downstream device 20 stores a table in its memory of the communication requirements of the device. Downstream hub 20 is then able to emulate the peripheral device 22 when communicating with the upstream hub 18 and to emulate the upstream device 18 when communicating with the peripheral device 22. Downstream hub 20 then establishes communication with upstream hub 18 over the wireless communication path 28 and conveys its information regarding the communication specifics of the peripheral device. In the meantime, it sends NAKs to the peripheral device 22 as is required by its response timeout, which "buys time" for the acknowledgement from host controller 14 to arrive. Upstream hub 18 sets up a proxy task dedicated to the downstream hub 20 and a table likewise listing the communication specifics of the peripheral device 22. In this way, as described above, the upstream hub 18 and the downstream hub 20 form a proxy which acts as the peripheral device when communicating to the host controller 14. The upstream hub 18 communicates the presence of the peripheral device 22 to the host controller 14 over connection 24, in a way that convinces the host controller 14 that it is the peripheral device 22. Host controller 14 acknowledges the peripheral device by sending an acknowledgement (ACK) signal to upstream hub 18. Upstream hub 18 assigns the ACK to the appropriate proxy task and transmits the ACK to the downstream hub 20 over the wireless communication path 28. Downstream hub 20 receives the ACK and commences its regular communication, packet by packet, with the peripheral device 22, which "thinks" that it is communicating directly with host controller 14.

Downstream hub 20 is then capable of carrying out proxy communications with its assigned proxy task on upstream hub 18, while using NAKs to buy time with the peripheral device 22 as necessary. Upstream hub 18 is then capable of carrying out proxy communications between the proxy task and the host controller 14, also using NAKs to buy time with the host controller 14 as necessary.

In order to insure that the wireless communication between the upstream hub 18 and the downstream hub 20 is secure, the present invention incorporates several security features. First, as described above, in the configuration stage of a downstream hub into the system, the downstream hub must be brought into close proximity with the upstream hub in order to carry out the configuration of the downstream hub via the serial interfaces 130 and 156 of the upstream hub 18 and the downstream hub 20, respectively. This instantiation security insures that, during the configuration process, an unintended downstream hub is not unknowingly configured into the system. Furthermore, the wireless communication_path 28 can be made secure by means of spread spectrum or any other technology designed to hide the communications in ambient atmospheric noise. Data encryption may also be used to encrypt the wireless communication packets, including public key encryption.

Accordingly, the present invention includes a wireless USB system that enables USB peripheral devices to communicate with a USB host controller of a personal computer without the use of a hard-line connection and from any reasonable distance away from the personal computer. The system meets Microsoft's compatibility requirements and therefore is purely "plug and play". The system includes a proxy hub which coordinates the communication between the host controller and the peripheral device and carries out the wireless transmission of the communication. While the invention can be used in conjunction with any type of USB peripheral device, it is especially advantageous when used in conjunction with video surveillance cameras, stereo speakers and telephones, in which the wireless transmission of signals eases installation constraints and enhances the portability of the devices. Although the invention has been described as a wireless USB system, it will be understood that other communication protocols may also be used, such as Firewire-IEEE 1394. The proxy scheme of the present invention can also be implemented into a system having a wired communication path, including ethernet, power line, telephone line and general wired media.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of the equivalency of the claims are therefore intended to be embraced therein.

Claims

L A system for communicating data signals between a computer processor and a peripheral device comprising: a controller device associated with said computer processor; a proxy device coupled to said controller device; and a peripheral device coupled to said proxy device; wherein said proxy device is adapted for: A. receiving a first data signal transmitted from one of said controller device and said peripheral device, and transmitting said first data signal to the other of said controller device and said peripheral device while instructing said one of said controller device and peripheral device to resend said first data signal; and B. receiving a second data signal from said other of said controller device and said peripheral device and transmitting said second data signal to said one of said controller device and said peripheral device in response to first data signal resent by said one of said controller device and said peripheral device.

2. The system of claim 1 wherein said proxy device comprises an upstream device coupled to said controller device and a downstream device coupled to said peripheral device, said upstream and downstream devices being couplable to each other by a communication path for transmitting said first and second data signals between said controller device and said peripheral device.

3. The system of claim 2 wherein said commumcation path is a wireless path.

4. The system of claim 3 wherein said wireless path is one of a radio frequency path and an infrared path.

5. The system of claim 4, wherein said controller device is a universal serial bus controller and said peripheral device is a universal serial bus peripheral device.

6. A method of communicating data signals between a computer processor and a peripheral device, comprising: A. transmitting a first data signal from a controller device associated with said computer processor to a proxy device; B. transmitting said first data signal from said proxy device to said peripheral device; C. transmitting a request from said proxy device to said controller device to resend said first data signal; D. transmitting a second data signal from said peripheral device to said proxy device; E. retransmitting said first data signal from said controller device to said proxy device; and F. transmitting said second data signal from said proxy device to said controller device in response to said retransmitted first data signal.

7. The method of claim 6 wherein step B comprises transmitting said control data signal from an upstream element of said proxy device to a downstream element of said proxy device and then transmitting said first data signal from said downstream element to said peripheral device.

8. The method of claim 7, wherein step C is performed by said upstream element.

9. The method of claim 8, wherein step F comprises transmitting said second data signal from said downstream element of said proxy device to said upstream element of said proxy device and then transmitting said second data signal from said upstream element to said controller device.

10. The method of claim 8, wherein said first data signal and said second data signal are transmitted between said upstream element and said downstream element over a wireless communication path.

11. The method of claim 11 , wherein said wireless communication path is one of a radio frequency path and an infrared path.

12. A system for communicating data signals between a computer processor and a peripheral device comprising: a controller device associated with said computer processor; a proxy device coupled to said controller device; and a peripheral device coupled to said proxy device; wherein said proxy device is adapted for: A. receiving request data signals transmitted from one of said controller device and said peripheral device, and transmitting said request data signals to the other of said controller device and said peripheral device while instructing said one of said controller device and peripheral device to resend said request data signals; and B. receiving response data signals from said other of said controller device and said peripheral device and transmitting said response data signals to said one of said controller device and said peripheral device in response to request data signals resent by said one of said controller device and said peripheral device.

13. The system of claim 12 wherein said proxy device comprises an upstream device coupled to said controller device and a downstream device coupled to said peripheral device, said upstream and downstream devices being couplable to each other by a communication path for transmitting said request and response data signals between said controller device and said peripheral device.

14. The system of claim 13 wherein said communication path is a wireless path.

15. The system of claim 14 wherein said wireless path is one of a radio frequency path and an infrared path.

16. The system of claim 15, wherein said controller device is a universal serial bus controller and said peripheral device is a universal serial bus peripheral device.

17. A method of communicating data signals between a computer processor and a peripheral device, comprising: A. transmitting a first data signal from said peripheral device to a proxy device; B. transmitting said first data signal from said proxy device to a controller device associated with said computer processor; C. transmitting a request from said proxy device to said peripheral device to resend said first data signal; D. transmitting a second data signal from said controller device to said proxy device; E. retransmitting said first data signal from said peripheral device to said proxy device; and F. transmitting said second data signal from said proxy device to said peripheral device in response to said retransmitted first data signal.

18. The method of claim 17 wherein step B comprises transmitting said first data signal from an upstream element of said proxy device to a downstream element of said proxy device and then transmitting said first data signal from said downstream element to said peripheral device.

19. The method of claim 18, wherein step C is performed by said upstream element.

20. The method of claim 19, wherein step F comprises transmitting said response data signal from said downstream element of said proxy device to said upstream element of said proxy device and then transmitting said second data signal from said upstream element to said controller device.

21. The method of claim 20, wherein said first data signal and said second data signal are transmitted between said upstream element and said downstream element over a wireless communication path.

22. A universal serial bus communication system comprising: a first hub device having a first port adapted for receiving and transmitting data signals in a USB format from and to an upstream device, a second port adapted for transmitting and receiving data signals in a wireless format, and a data signal conversion device adapted for converting said data signals in said USB format to said data signals in said wireless format and for converting said data signals in said wireless format to said data signals in said USB format; and a second hub device having a first port adapted for receiving and transmitting data signals in said wireless format from and to said second port of said first hub device, a second port adapted for receiving and transmitting data signals in said USB format from and to a downstream device, and a data signal conversion device adapted for converting said data signals in said USB format to said data signals in said wireless format and for converting said data signals in said wireless format to said data signals in said USB format.

AMJ_.ΓNDI_D CLAIMS

[received by the International Bureau on 25 April 2001 (25.04.01); new claims 23-34 added; remaining claims unchanged (2 pages)] 23. The system of claim 22 wherein said wireless format is one of an infrared format and a radio frequency format.

24. The system of claim 22 wherein said first hub device includes a first transceiver coupled to said first port for transmitting and receiving said data signals in said USB format to and from said upstream device and wherein said first data signal conversion device includes a second transceiver coupled to said second port and a first signal processor for: A. receiving said USB data signals from said first transceiver, converting said USB signal to a wireless signal and outputting said wireless signal to said second transceiver; and B receiving said wireless data signals from said second transceiver, converting said wireless data signal to said USB data signal and outputting said USB data signal to said first transceiver.

25. The system of claim 24 wherein said second hub device includes a third transceiver coupled to said first port for transmitting and receiving said data signals in said USB format to and from said downstream device and wherein said second data signal conversion device includes a fourth transceiver coupled to said second port and a second signal processor for: A. receiving said USB data signals from said first transceiver, converting said USB signal to a wireless signal and outputting said wireless signal to said second transceiver; and B receiving said wireless data signals from said second transceiver, converting said wireless data signal to said USB data signal and outputting said USB data signal to said first transceiver.

26. The system of claim 23 wherein said first hub device includes plurality of proxy devices adapted for receiving and transmitting said data signals in a USB format from and to said upstream device and for transmitting and receiving data signals in a wireless format to and from said second hub device.

27. The system of claim 23 wherein said second hub device includes a plurality of hubs, each being adapted for receiving and transmitting said data signals in said wireless format from and to said first hub device and for receiving and transmitting data signals in said USB format from and to said downstream device.

28. The system of claim 23 wherein said first hub device includes plurality of proxy devices adapted for receiving and transmitting said data signals in a USB format from and to said upstream device and for transmitting and receiving data signals in a wireless format to said second hub device and wherein said second hub device includes a plurality of hubs, each being adapted for receiving and transmitting said data signals in said wireless format from and to said first hub device and for receiving and transmitting data signals in said USB format from and to said downstream device.

29. A method of transmitting USB signals from an upstream device to a downstream device compri ^'s ;iinngg: A. transmitting a first data signal from said upstream device to a first hub, said first data signal being in a USB format; B. converting, in said first hub, said first data signal from said USB format to a second data signal in a wireless format; C. transmitting said second data signal from said first hub to a second hub; D. converting, in said second hub, said second data signal from said wireless format to a third data signal in said USB format; and E. transmitting said third data signal from said second hub to said downstream device.

30. The method of claim 29, wherein step C further includes transmitting a NAK signal from said first hub to said upstream device.

31. The method if claim 30, further comprising retransmitting said first data signal from said upstream device to said first hub in response to said NAK signal..

32. The method of claim 31 further comprising: F. transmitting a first response signal from said downstream device to said second hub in response to said third data signal, said first response signal being in said USB format; G. converting, in said second hub, said first response signal from said USB format to a second response signal in said wireless format; H. transmitting said second response signal from said second hub to said first hub; I. converting, in said first hub, said second response signal from said wirelss format to a third response signal in said USB format; and J. transmitting said third response signal from said wireless format from said first hub to said upstream device in response to said retransmitted first data signal.

33. The method of claim 32 further comprising attaching a time stamp to said third response signal in said first hub.

34. The method of claim 33 wherein step J further includes searching a memory of said first hub and transmitting said third response signal having a most recent time stamp to said upstream device,