Patent Publication Number: US-7586843-B1

Title: Communication network having wireless access to a service center

Description:
RELATED APPLICATIONS 
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   FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   MICROFICHE APPENDIX 
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   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention is related to the field of communications, and in particular, to communication networks that provide wireless access to communication services. 
   2. Description of the Prior Art 
   User demand for wireless access to communication services is rapidly growing. In a typical wireless access scenario, a user operates a wireless communication device to exchange wireless communication signals over the air with a wireless access point. The wireless access point exchanges the user communications with a service center over a communication network. The service center processes the user communications to provide a service, such as telephony communication, Internet access, or video streaming. 
   Examples of wireless communication devices include mobile telephones, personal digital assistants, and laptop computers. Examples of wireless access points include base stations, WIFI hotspots, and antenna systems. Examples of service centers include mobile switching centers, Internet access points, and media servers. Examples of wireless formats include CDMA, WIFI, and WIMAX. 
   As the user demand for wireless access to communication services has increased, so has the deployment of wireless access points. Various communication networks have been developed to exchange user communications between the growing number of wireless access points and the service center. Unfortunately, these communication networks have not been optimized for both efficiency and reliability. 
     FIG. 1  illustrates an example of a prior communication network that exchanges user communications between wireless access points and a service center (the wireless access points use the acronym WAP on the figures). Note that groups of proximate wireless access points are coupled in series to form a serial route to the service center. Each wireless access point has a point-to-point communication link to the service center in the serial route. 
   For example, wireless access points A, B, and C each have their own point-to-point communication link to the service center that follows the serial route. If there is a fault (indicated by an “X” mark on the figures) on the serial route between wireless access point B and wireless access point C, then the point-to-point communication links from wireless access points A and B to the service center are lost. 
     FIG. 2  illustrates another example of a prior communication network that exchanges user communications between wireless access points (WAPs) and a service center. Note that the service center is now coupled to a central communication ring. Also note that groups of proximate wireless access points are coupled to collector communication rings. Each collector ring is coupled to the central ring through a ring node. Thus, the wireless access points communicate with the service center over the collector rings and the central ring. 
   Each wireless access point has a point-to-point communication link over the rings to the service center. For example, wireless access point B has a point-to-point communication link to the service center through wireless access point C and ring nodes E and F (B-C-E-F-SC). For back-up in the event of a fault, wireless access point B has a second point-to-point link to the service center through wireless access point A and ring nodes E and D (B-A-E-D-SC). 
   For a fault on the collector ring between wireless access point B and wireless access point C, wireless access point B and the service center would switch user communications from the failed first link (B-C-E-F-SC) to the operational second link (B-A-E-D-SC). Likewise, for a fault on the central ring between ring node E and ring node F or between ring node F and the service center, wireless access point B and the service center would switch user communications from the failed first link (B-C-E-F-SC) to the operational second link (B-A-E-D-SC). 
   Unfortunately, there are still problems with the prior communication network of  FIG. 2 . If a ring node fails, then the wireless access points that are served by the failed ring node cannot communicate with the service center. For example, if ring node E fails, then wireless access points A, B, and C cannot communicate with the service center over any of the point-to-point communication links. 
   In addition, the point-to-point links typically have a dedicated amount of bandwidth that goes unused—especially on the back-up links. Thus, the point-to-point links between the wireless access points and the service center represent an inefficient use of bandwidth. 
   SUMMARY OF THE INVENTION 
   Examples of the invention include a communication network. The communication network comprises a communication ring including a first communication node, a second communication node, a third communication node, and a fourth communication node. The communication network comprises a first communication loop coupled to separate points on the communication ring through the first communication node and the second communication node. The communication network comprises a second communication loop coupled to separate points on the communication ring through the third communication node and the fourth communication node. The communication network comprises a service center coupled to the communication ring. The communication network comprises a first set of wireless access points coupled to the first communication loop. The communication network comprises a second set of wireless access points coupled to the second communication loop. The wireless access points are configured to exchange user communications in a wireless communication format with user wireless communication devices. The wireless access points and the communication nodes are configured to exchange the user communications over the communication loops. The communication nodes and the service center are configured to exchange the user communications over the communication ring. 
   In some examples of the invention, the wireless access points and the communication nodes are configured, in response to a fault on one of the communication loops, to re-route the user communications to avoid the fault on the one communication loop. 
   In some examples of the invention, the communication nodes and the service center are configured, in response to a fault on the communication ring, to re-route the user communications to avoid the fault on the communication ring. 
   In some examples of the invention, the wireless access points and the communication nodes each include internet protocol routers that are configured to exchange the user communications over the communication loops using the internet protocol, and in response to a fault on one of the communication loops, to re-route the user communications using the internet protocol to avoid the fault on the one communication loop. 
   In some examples of the invention, the service center includes an internet protocol router and wherein the internet protocol routers in the communication nodes and the service center are configured to exchange the user communications over the communication ring using the internet protocol, and in response to a fault on the communication ring, to re-route the user communications using the internet protocol to avoid the fault on the communication ring. 
   In some examples of the invention, the communication loops comprise Ethernet links. 
   In some examples of the invention, the communication ring comprises an optical ring. 
   In some examples of the invention, the communication ring comprises a Synchronous Optical Network ring. 
   In some examples of the invention, the communication ring comprises a metropolitan area network. 
   In some examples of the invention, the wireless communication format comprises Code Division Multiple Access (CDMA). 
   In some examples of the invention, the wireless communication format comprises WIFI. 
   In some examples of the invention, the wireless communication format comprises WIMAX. 
   In some examples of the invention, the service center provides telephony service. 
   In some examples of the invention, the service center provides Internet access service. 
   In some examples of the invention, the service center provides video streaming service. 
   In some examples of the invention, the service center comprises a mobile switching center. 
   In some examples of the invention, the user wireless communication devices comprise mobile telephones. 
   In some examples of the invention, the user wireless communication devices comprise personal digital assistants. 
   In some examples of the invention, the user wireless communication devices comprise laptop computers. 
   In some examples of the invention, the first communication loop and the second communication loop are not closed to form rings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The same reference number represents the same element on all drawings. 
       FIG. 1  illustrates a communication system with serially-connected communication nodes in an example of the prior art. 
       FIG. 2  illustrates a communication system experiencing a ring fault in an example of the prior art. 
       FIG. 3  illustrates a communication system including loops in an example of the invention. 
       FIG. 4  illustrates a communication system including Internet protocol routers in an example of the invention. 
       FIG. 5  illustrates a communication system experiencing a loop fault in an example of the invention. 
       FIG. 6  illustrates a communication system experiencing a ring fault in an example of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The following description and associated figures teach the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects of the best mode may be simplified or omitted. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Thus, those skilled in the art will appreciate variations from the best mode that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents. 
   EXAMPLE #1 
     FIG. 3  illustrates communication network  100  in an example of the invention. Communication network  100  includes communication ring  107 ; communication loops  110 ,  120 , and  130 ; wireless access points (WAPs)  111 - 113 ,  121 - 123 , and  131 - 133 ; and service center  140 . Communication ring  107  includes ring nodes  101 - 106 . Service center  140  is coupled to communication ring  107 . 
   Wireless access points  111 - 113  are coupled to communication loop  110 . The open ends of loop  110  are respectively coupled to ring nodes  101  and  102 . Wireless access points  121 - 123  are coupled to communication loop  120 . The open ends of loop  120  are respectively coupled to ring nodes  103  and  104 . Wireless access points  131 - 133  are coupled to communication loop  130 . The open ends of loop  130  are respectively coupled to ring nodes  105  and  106 . 
   Note that communication loops  110 ,  120 , and  130  are not rings, because loops  110 ,  120 , and  130  have open ends that do not close. Instead, the open ends of communication loops  110 ,  120 , and  130  are coupled to communication ring  107  through nodes  101 - 106 . Note that each communication loop  110 ,  120 , and  130  is coupled to the communication ring  107  at two separate points. 
   Wireless access points  111 - 113 ,  121 - 123 , and  131 - 133  are each configured to exchange user communications in a wireless communication format with user wireless communication devices (not shown). Examples of the wireless communication devices include mobile telephones, personal digital assistants, and laptop computers although there could be other types of wireless communication devices. Examples of wireless communication formats include Code Division Multiple Access (CDMA), WIFI, and WIMAX, although there could be other types of wireless communication technology. Wireless access points  111 - 113 ,  121 - 123 , and  131 - 133  could be base stations, WIFI hotspots, antenna systems, or some other communication system that communicates with user devices using a wireless communication format. 
   Wireless access points  111 - 113  and ring nodes  101 - 102  exchange the user communications over loop  110 . Ring nodes  101 - 102  and service center  140  exchange the user communications over communication ring  107 . Thus, wireless access points  111 - 113  and service center  140  exchange the user communications over loop  110  and ring  107 . Wireless access points  121 - 123  and ring nodes  103 - 104  exchange the user communications over loop  120 . Ring nodes  103 - 104  and service center  140  exchange the user communications over communication ring  107 . Thus, wireless access points  121 - 123  and service center  140  exchange the user communications over loop  120  and ring  107 . Wireless access points  131 - 133  and ring nodes  105 - 106  exchange the user communications over loop  130 . Ring nodes  105 - 106  and service center  140  exchange the user communications with over communication ring  107 . Thus, wireless access points  131 - 133  and service center  140  exchange the user communications over loop  130  and ring  107 . 
   Communication loops  110 ,  120 , and  130  could be comprised of packet links, time division multiplex links, or wireless links, although other types of communication links could be used. Ring nodes  101 - 106  could be multiplexers, switches, or routers, although other types of nodes could be used. 
   Service center  140  processes the user communications to provide at least one communication service. Service center  140  could be a mobile switching center, Internet access point, media server, or some other system that provides a communication service. Examples of communication services include telephony communication, Internet access, and video streaming, although there could be other communication services. 
   The wireless access points, ring nodes, and service center described above provide re-routing in case of a fault. In response to a fault on one of the communication loops, the wireless access points and ring nodes affected by the fault re-route the user communications around the other side of the faulty loop to avoid the fault. In response to a fault on the communication ring, the ring nodes and service center affected by the fault re-route the user communications around the other side of the ring to avoid the fault. 
   EXAMPLE #2 
     FIGS. 4-6  illustrate communication network  200  in an example of the invention. Communication network  200  includes communication ring  207 , communication loop  210 , wireless access points  211 - 213 , and service center  240 . Communication ring  207  includes ring nodes  201 - 202 . Ring nodes  201 - 202  include respective internet protocol routers  301 - 302 . Wireless access points  211 - 213  include respective internet protocol routers  311 - 313 . Service center  240  includes internet protocol router  340 . For clarity, only one communication loop, three wireless access points, and two ring nodes are shown, but additional communication loops, ring nodes, and wireless access points that are configured and operate as described below could be added. 
   Service center  240  is coupled to communication ring  207 . Wireless access points  211 - 213  are coupled to communication loop  210 . The open ends of loop  210  are respectively coupled to ring nodes  201  and  202 . Note that communication loop  210  is not a ring, because loop  210  has open ends that do not close. Instead, the open ends of communication loop  210  are coupled to communication ring  207  through nodes  201 - 202 . Note that communication loop  210  is coupled to the communication ring  207  at two separate points. 
   Communication loop  210  is comprised of Ethernet links that transfer internet protocol packets between the internet protocol routers. Routers  301  and  311  are coupled by a first Ethernet link in loop  210 . Routers  311  and  312  are coupled by a second Ethernet link in loop  210 . Routers  312  and  313  are coupled by a third Ethernet link in loop  210 . Routers  313  and  302  are coupled by a fourth Ethernet link in loop  210 . Additional Ethernet links between the routers could be added as desired. 
   Communication ring  207  comprises optical links that transfer internet protocol packets between internet protocol routers. Router  301  is coupled to router  340  by first and second optical links around opposing sides of ring  207 . Router  302  is coupled to router  340  by third and fourth optical links around opposing sides of ring  207 . Additional optical links between the routers could be added as desired. Communication ring  207  could be a self-healing Synchronous Optical Network (SONET) ring that forms a metropolitan area network, although other types of optical networks could be used. Ring nodes  201 - 202  could be SONET add/drop multiplexers with Ethernet and internet protocol interfaces, although other types of optical nodes could be used. 
   Wireless access points  211 - 213  are each configured to exchange user communications in a wireless communication format with user wireless communication devices (not shown). Examples of the wireless communication devices include mobile telephones, personal digital assistants, and laptop computers although there could be other types of wireless communication devices. Examples of wireless communication formats include Code Division Multiple Access (CDMA), WIFI, and WIMAX, although there could be other types of wireless communication technology. Wireless access points  211 - 213  could be base stations, WIFI hotspots, antenna systems, or some other communication system that communicates with user devices using a wireless communication format. 
   Wireless access points  211 - 213  and ring nodes  201 - 202  exchange the user communications over loop  210 . Ring nodes  201 - 202  and service center  240  exchange the user communications over communication ring  207 . Thus, wireless access points  211 - 213  and service center  240  exchange the user communications over loop  210  and ring  207 . Service center  207  processes the user communications to provide at least one communication service. Service center  207  could be a mobile switching center, Internet access point, media server, or some other system that provides a communication service. Examples of communication services include telephony communication, Internet access, and video streaming, although there could be other communication services. 
   The exchange of user communications between wireless access point  212  and service center  240  is now described in more detail. Wireless access point  212  transfers user communications that are destined for service center  240  to router  312 . Wireless access point  212  may transfer internet protocol packets containing the user communication to router  312 , where the packets are addressed to service center  240 . Alternatively, wireless access point  212  could transfer the user communication to router  312 , and router  312  could packetize the user communications with the appropriate address of service center  240 . 
   Router  312  transfers the packets having the user communications to router  311 , and in response to the packet address, router  311  transfers the packets to router  301 . In response to the packet address, router  301  transfers the packets to router  340 , and router  340  transfers the packets to service center  240 . Alternatively, router  340  could de-packetize the user communication and transfer the de-packetized user communication to service center  240 . A reciprocal operation occurs to transfer user communications from service center  240  to wireless access point  212 . 
   Referring to  FIG. 5 , if there is a fault on loop  210  between wireless access points  211  and  212 , router  312  senses the fault and transfers the packets to router  313  to avoid the fault. In response to the packet address, router  313  transfers the packets to router  302 . In response to the packet address, router  302  transfers the packets to router  340 , and router  340  transfers the packets to service center  240 . Alternatively, router  340  could de-packetize the user communications in response to the packet address, and then transfer the de-packetized user communications to service center  240 . A reciprocal operation would occur to transfer user communications from service center  240  to wireless access point  212  and avoid the fault. 
   Referring to  FIG. 6 , if there is a fault on ring  207  between ring node  101  and service center  240 , router  301  senses the fault and transfers the packets around the other side of ring  207  to router  340 . Alternatively, SONET fault detection and re-routing could be used to avoid the fault. In response to the packet address, router  340  transfers the packets to service center  240 . Alternatively, router  340  could de-packetize the user communications in response to the packet address, and transfer the de-packetized user communications to service center  240 . A reciprocal operation would occur to transfer user communications from service center  240  to wireless access point  212  and avoid the fault. 
   Although communication network  200  is described as using the internet protocol, other packet protocols and routers could be used in a similar manner if desired. 
   CONCLUSION 
   Advantageously, communication networks utilizing the invention avoid the lack of reliability of the prior communication network depicted in  FIG. 1 . Communication networks utilizing the invention also avoid the single point-of-failure in the prior communication network depicted in  FIG. 2 . Communication networks utilizing the invention may also employ packet routing instead of the point-to-point communication links in the prior communication networks depicted in  FIGS. 1-2 . Packet routing enjoys the efficiencies of statistical multiplexing the uses bandwidth more efficiently. Thus, communication networks utilizing the invention can be more reliable and more efficient than prior networks.