WiFi phone system

• US 8,503,340 B1
• Filed: 07/11/2004
• Issued: 08/06/2013
• Est. Priority Date: 07/11/2004
• Status: Active Grant

• Current Assignee: Yongyong Xu
• Original Assignee: Yongyong Xu
• Inventors: Xu, Yongyong
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): ANDREWS, LEON T
• Application Number:
  US10/710,436
• Time in Patent Office: 3,313 Days
• Field of Search: 370/310, 370/320, 370/335, 370/342, 370352-357, 370/395.21, 370/395.52, 370/395.65, 370/401, 370/441, 370/908, 370/910, 370/912, 370/913, 370/211, 455 301- 305, 455/412.1, 455/555, 455/556.1, 455/556.2, 455/557, 455/452.2, 455/435.1, 709/226, 705/26
• US Class Current: 370/310
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A voice communication system over WiFi 802.11 network includes: WiFi phone devices, subscription servers and wireless access points. Through voice and data gateways the system can transfer both voice and data streams through WiFi; Phone devices with both wired and WiFi wireless interfaces can automatically switches between wired network and wireless network through WiFi access points. Subscription server maintains the current status of each device every time it changes location. Voice packets are prioritized over regular data packets and dispatched to different network interface by smart packet dispatcher. Quality of service for voice conversation over WiFi is achieved by various methods: piggy-tail method and ACK enhancements and other improvements to reduce delay and latency of real time voice packets.

Claims

1. A WiFi phone system capable of providing voice calls over either a WiFi wireless network or a wired network and of allowing WiFi phone devices to freely move within a group of networks comprising:

WiFi wireless access points coupled to each other through a network;

WiFi phone devices with built-in wired and WiFi wireless interfaces, wherein;

said WiFi phone devices allow real time phone conversations directly through either the wired or the WiFi wireless interface; and

said WiFi phone devices automatically switch to said wired interface to conduct real-time bidirectional phone calls if said WiFi phone devices are attached to said wired network and wherein said WiFi wireless interface continues to be used as a secondary communication channel;

otherwise, said WiFi phone devices switch to said WiFi wireless interface to place phone calls, and transmit and receive voice and data packets simultaneously;

a voice gateway coupled to either of the network, wherein said voice gateway is capable of;

placing, routing and receiving external phone calls through said wired interface if said WiFi phone devices are attached to said wired network; and

placing, routing and receiving external phone calls through said WiFi wireless interface if said WiFi phone devices are only connected through said WiFi wireless network; and

a subscription server operated to maintain a status of each of the WiFi phone devices wherein;

each of said WiFi phone devices notifies said subscription server when they move to another network within said group of networks;

said subscription server updates a location for each of said WiFi phone devices; and

said subscription server notifies said voice gateway and said WiFi wireless access points in the group of networks of updated location of each of said WiFi phone devices to switch the routing of incoming calls and a transmission and receipt of both voice and data packets; and

a smart packet dispatcher in said WiFi phone device operated to improve response time for real time packets by setting up two queues, one for voice or real time packets, and the other for regular data packets, the smart packet dispatcher emptying the voice or real time packet queue before the regular data packet queue so that the voice or real time packets are delivered with improved response time.

2. The WiFi phone system of claim 1, wherein said voice gateway is operated to bridge an external phone network to the group of networks.

3. The WiFi phone system of claim 1, further comprising a data gateway coupled to the group of networks and operated to bridge an external data network to the group of networks.

4. The WiFi phone system of claim 1, wherein the WiFi wireless access points support different 802.11 wireless protocols selected from among 802.11b, 802.11a or 802.11g.

5. The WiFi phone system of claim 1, wherein the wired interface can be implemented by a cradle connected to the group of networks directly, or by a built-in network card with an Ethernet or POE (Power over Ethernet) connector, or other wired network connector.

6. The WiFi phone system of claim 1, wherein the WiFi phone devices are operated to automatically switch between the WiFi wireless interface and the wired interface based on connection speed.

7. The WiFi phone system of claim 1, wherein the wired and wireless interfaces include WiMAX, GSM, CDMA, 3G or other cellular phone interfaces.

8. The WiFi phone system of claim 1, wherein voice calls over the group of networks use Voice over IP technology.

9. The WiFi phone system of claim 1, wherein the subscription server maintains a database to keep track of a current status of each of the WiFi phone devices, the current status including IP address, MAC address, and access point, the database being updated when each of the WiFi phone devices changes its status.

10. The WiFi phone system of claim 1, wherein the subscription server provides a means for locating each of the WiFi phone devices in the case of an incoming call.

11. The WiFi phone system of claim 1, wherein the subscription server can direct calls to use more reliable or faster routers in the group of networks for better performance and send routing information packets to the routers of the group of networks to achieve quality of service.

12. The WiFi phone system of claim 1, wherein each of the WiFi phone devices is operated to send the subscription server an updated status.

13. The WiFi phone system of claim 1, wherein the subscription server is operated to monitor each of the WiFi phone devices and update its status.

14. The WiFi phone system of claim 1, wherein the WiFi wireless access points and the WiFi phone devices utilize QoS (Quality of Service) to prioritize voice packets.

15. The WiFi phone system of claim 1, wherein the voice gateway is operated to consult with the subscription server to locate a WiFi phone.

35. The WiFi phone system of claim 1, wherein backward compatibility is achieved by reducing a group size to 1.

36. The WiFi phone system of claim 1, wherein the WiFi phone device or access point is further operated to improve voice communication performance by piggy-tailing the voice or real time packets with the regular data packets in an 802.11 wireless WiFi network to reduce extra overhead, waste, and latencies.

37. The WiFi phone system of claim 1, wherein the WiFi phone device or access point is further operated to improve quality of service by specifying smaller back-off time on collision for voice or real time packets transferred between the WiFi phone device and the WiFi access points.

38. The WiFi phone system of claim 1, wherein the WiFi phone device or access point is further operated to improve the voice communication performance by specifying a larger timeout value to postpone 802.11 ACK packets.

39. The WiFi phone system of claim 1, wherein the WiFi phone device or access point is further operated to improve the voice communication performance by sending ACK packets after receiving a group of packets, the group size being based on the types of packets and connection conditions.

40. The WiFi phone system of claim 1, wherein the WiFi phone device or access point is further operated to improve the voice communication performance by sending a NACK packet for each packet error.

16. A WiFi phone device capable of making voice calls over either a WiFi wireless network or a wired network and capable of freely moving within a group of networks comprising:

a built-in WiFi wireless interface and a built-in wired interface, wherein;

said WiFi phone device automatically switches to said wired interface to allow real time bidirectional phone calls if said WiFi phone device is attached to said wired network;

said WiFi phone device automatically routes to said WiFi wireless interface to place phone calls if said WiFi phone device is not connected to said wired network; and

a component operated to automatically switch between the WiFi wireless interface and the wired interface for both voice calls and data communications wherein;

said WiFi phone device notifies a subscription server when it moves from one network to another network;

said subscription server maintaining and updating a location of said WiFi phone device;

said subscription server notifying a voice gateway in the group of networks of said location change of said WiFi phone device to route incoming calls and to transmit and receive both voice and data packets simultaneously, wherein said voice gateway is capable of;

placing, routing and receiving external phone calls through said wired interface if said WiFi phone device is attached to said wired network; and

placing, routing and receiving external phone calls through said WiFi wireless interface if said WiFi phone device is only connected through said WiFi wireless network; and

a smart packet dispatcher in said WiFi phone device operated to improve response time for real time packets by setting up two queues, one for voice or real time packets, and the other for regular data packets, the smart packet dispatcher emptying packets in the voice or real time packet queue before the regular data packet queue so that the voice or real time packets are delivered with improved response time.

17. The WiFi phone device of claim 16, wherein the wired interface is implemented by a cradle connected to the group of networks or by a built-in network card with Ethernet or a POE (Power over Ethernet) connector or other wired network connector.

18. The WiFi phone device of claim 17, wherein the cradle can be used for charging the WiFi phone device and as a network connector.

19. The WiFi phone device of claim 17, wherein a POE cable can be used for charging the WiFi phone device and as a network connection with a simple plug-able connector.

20. The WiFi phone device of claim 16, wherein the WiFi phone device is capable of running a mobile application simultaneously with a voice call.

21. The WiFi phone device of claim 16, wherein the WiFi phone device uses a mobile operating system including Palm OS, Windows CE, Symbian, embedded Linux or any other embedded system.

22. The WiFi phone device of claim 16, wherein the WiFi phone device is compatible with Voice over IP phones when connected through the wired interface.

23. The WiFi phone device of claim 16, wherein every time the WiFi phone device changes mode or detects an environmental change, the WiFi phone device sends a notification to the subscription server to update its current status, the current status including its location, address, gateway or access point.

24. The WiFi phone device of claim 16, wherein the smart packet dispatcher is operated to determine the priority of a packet by its header, port number or DSCP (Differentiated Services Code Point) field in the IP header of the packet.

25. The WiFi phone device of claim 16, wherein the WiFi wired interface extends to a non-WiFi wireless interface selected from among GSM, CDEMA, 3G or other cellular interface.

26. The WiFi phone device of claim 16, wherein the WiFi wireless interface extends to a packet switched wireless interface selected from among WiMAX, GSM, CDMA, 3G or other cellular interface.

41. The WiFi phone device of claim 16, wherein the WiFi phone device is further operated to improve the voice communication performance by either piggy-tailing the voice or real time packets with regular data packets to reduce extra overhead, waste, and latencies or by reducing ACK acknowledgment through larger timeout value usage of NACK.

27. A method of piggy-tailing voice or real time packets with regular data packets in an 802.11 wireless WiFi network to reduce extra overhead, waste, latencies and to improve quality of service between two machines in a single device with both built-in WiFi wireless and wired interfaces comprising the steps of:

setting up a regular data packet queue and a voice or real time packet queue;

a sender finding a small regular data packet from a data packet queue that contains data packets to be sent, the small regular data packet having a smaller size than a frame size, said sender determining a remaining space from the frame size;

said sender locating a voice or real time packet from a voice or real time packet queue that contains voice or real time packets to be sent;

if the size of said voice or real time packet is larger than the remaining space then;

said sender splitting said voice or real time packet into multiple small packets

otherwise, said sender keeping the voice or real time packet intact;

said sender appending each of said multiple small packets or said intact voice or real time packet to the small regular data packet to form a larger packet;

said sender adding special flags in the larger packet header to denote the larger packet as a piggy-tailing packet; and

a receiver of said larger packet re-assembling the voice or real time packets from the received larger packet based on the special flag in the packet header.

28. The method of claim 27, further comprising determining if the voice or real time packet is large or small and splitting the voice or real time packet into multiple small packets only in the case where the voice or real time packet is large.

29. The method of claim 27, wherein the regular data packet includes IP, TCP, UDP or other Internet packets.

30. The method of claim 27, wherein the voice or real time packets are UPD, RTP, or other real time packets.

31. The method of claim 30, wherein the voice or real time packets are recurring small packets that require immediate delivery.

32. The method of claim 27, further comprising detecting the voice or real time packets by looking up a header including a port number.

33. A method of reducing extra overhead and improving response time for voice or real time packets in a 802.11 wireless protocol in a single device handling both voice or real time packets and regular data packets comprising the steps of:

determining the majority type of packets to be delivered by the network;

if the majority type of packets to be delivered is voice or real time packets, announcing within a WiFi network the use of a smaller back-off waiting time when there is collision between WiFi access points and devices;

postponing sending 802.11 ACK packets by specifying a larger timeout value;

sending ACK packets after receiving a group of packets, the group size being based on the types of packets and connection conditions; and

sending a NACK packet for each packet error;

otherwise, if the majority type of packets to be delivered is regular data packets;

announcing within the WiFi network the use of a regular waiting time when there is collision between WiFi access points and devices;

using a regular ACK timeout value;

using a regular ACK mechanism; and

stopping the use of NACK packet for each packet error.

34. The method of claim 33, further comprising detecting the voice or real time packets by looking up a header including a port number.