Patent Abstract:
A distributed wireless digital subscriber line (DSL) network. The invention system and method allows service providers to extend their reach over the final segment within the communication system with broadband services. A small, wireless broadband access point (WBAP) may be installed on a facility&#39;s exterior (e.g., a home or office building) or at the localized box that provides service to a user. The greater the number of WBAPs and the greater the density of WBAPs within a given locale, then the greater the wireless DSL network coverage area, and the greater the signal-to-noise ratio (SNR) that may be achieved when the service coverage areas of two or more WBAPs overlap. The invention provides a truly distributed wireless DSL network, enabling broadband services, throughout a service provider&#39;s coverage area. Each service area&#39;s wireless spectrum may be independently managed to ensure total coverage throughout the network.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    The following U.S. patent application is hereby incorporated herein by reference in its entirety and made part of the present U.S. patent application for all purposes:  
         [0002]    U.S. patent application Ser. No. 10/137,624, entitled “Digital Subscriber Line Head-End,” (Attorney Docket No. CEL02004), filed May 2, 2002. 
     
    
     
       BACKGROUND  
         [0003]    1. Technical Field  
           [0004]    The invention relates generally to communication systems; and, more particularly, it relates to a distributed wireless digital subscriber line network.  
           [0005]    2. Related Art  
           [0006]    Current approaches for providing broadband Internet access using digital subscriber line (DSL) services are complex and expensive to deploy. In the residential context, there is the difficulty in spanning that last segment of infrastructure to a user&#39;s site. This is the segment of the network, often referred to as “the last mile,” which presents the most significant bottleneck in terms of ensuring broadband services to a user. While there has been discussion of providing broadband (e.g., fiber-optic) cabling up to every user site, there are virtually no examples of this cabling solution that have been implemented.  
           [0007]    Even if a service provider uses a “brute force” cabling solution to provide broadband access to a facility, it is often necessary to extend the broadband access to multiple users within the facility. Many business users provide multiple user access with a local area network within the facility. There is a need, therefore, for a cost-effective solution for providing broadband service over the “last mile” to multiple users.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    A better understanding of the invention can be obtained when the following detailed description of various exemplary embodiments is considered in conjunction with the following drawings.  
         [0009]    [0009]FIG. 1 is a system diagram illustrating an embodiment of a distributed wireless digital subscriber line (DSL) network that is built in accordance with the present invention.  
         [0010]    [0010]FIG. 2 is a system diagram illustrating another embodiment of a distributed wireless DSL network that is built in accordance with the present invention.  
         [0011]    [0011]FIG. 3 is a system diagram illustrating another embodiment of a distributed wireless DSL network that is built in accordance with the present invention.  
         [0012]    [0012]FIG. 4 is a system diagram illustrating another embodiment of a distributed wireless DSL network that is built in accordance with the present invention.  
         [0013]    [0013]FIG. 5 is a system diagram illustrating an embodiment of a RAKE receiver implemented within a distributed wireless DSL network that is built in accordance with the present invention.  
         [0014]    [0014]FIG. 6 is a functional block diagram illustrating an embodiment of a distributed wireless DSL network method that is performed in accordance with the present invention.  
         [0015]    [0015]FIG. 7A is a functional block diagram illustrating an embodiment of a distributed wireless DSL network downstream communication method that is performed in accordance with the present invention.  
         [0016]    [0016]FIG. 7B is a functional block diagram illustrating an embodiment of a distributed wireless DSL network upstream communication method that is performed in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIG. 1 is a system diagram illustrating an embodiment of a distributed wireless digital subscriber line (DSL) network  100  in accordance with the present invention. A central office  105  is communicatively coupled to a plurality of subscribers via distribution equipment arranged in a variety of configurations that will be discussed in greater detail hereinbelow.  
         [0018]    The embodiment shown in the FIG. 1 illustrates a digital subscriber line head-end  112  (sometimes referred to herein as a “head-end”) communicatively coupled to the CCB  111  and a head-end  114  communicatively coupled to the CCB  113 . In addition, a head-end may be communicatively coupled directly to the NG-DLC  102 , as shown by the dotted lines of a head-end  104 . Alternatively, a head-end  106  may be communicatively coupled directly to the central office  105 , as shown by the dotted lines on head-end  106 . Fiber-optic cabling may be provisioned up to the NG-DLCs or the digital subscriber line head-ends where an optical switch is included to perform the optical coupling from the optical fiber to the metal wire that still exists along the remaining distance to the subscribers. In this configuration, the DSL may be brought over an F 1  (main feed) cable to a CCB. As mentioned above, a head-end may be added to each CCB, or to each distribution area. Each of the CCBs is operable to provide servicing via F 2  (distribution) cables to subscriber groups/neighborhoods. However, a smaller number of subscribers may also be communicatively coupled to the CCBs or the NG-DLCs.  
         [0019]    In one configuration shown in the FIG. 1, the central office  105  communicatively couples to the NG-DLC  101  that in turn communicatively couples to the CCB  111  (and the associated head-end  112 ) that is situated in very close proximity to it. The head-end  112  services a number of subscribers, shown as subscribers  151 ,  152 , . . . , and  159 . Each of the subscribers  151 ,  152 , . . . , and  159  is provided with a wireless broadband access point (WBAP). The WBAPs serve as customer premises equipment (CPE) in the embodiment where the WBAPs are installed at each subscriber&#39;s location. For example, the subscriber  151  is provided with the WBAP  161 ; the subscriber  152  is provided with the WBAP  162 ; . . . ; and the subscriber  159  is provided with the WBAP  169 . The WBAPs include a wireless transceiver/antenna that provides for wireless DSL communication within a WBAP wireless access region. As will be seen in other embodiments discussed hereinbelow, the WBAP wireless access regions sometimes overlap, thereby providing additional gains in SNR within those regions.  
         [0020]    In another configuration illustrated in FIG. 1, the central office  105  communicatively couples directly to subscribers  171  and  172 . Each of the subscribers  171  and  172  is connected to a WBAP. For example, the subscriber  171  is connected to the WBAP  181  and the subscriber  172  is connected to the WBAP  182 . Each of these subscribers  171  and  172  may be provided with broadband services directly from the central office  105  via the head-end  106 . Subscriber  173  may be provided with broadband service via the head-end  114  connected to the CCB  113 . The present invention is adaptable to accommodate any of these variations. In addition, the CCB  113 , along with its associated head-end  114 , service the subscriber  173  along with its associated WBAP  183 .  
         [0021]    Referring again to FIG. 1, the central office  105  is also shown communicatively coupled to a NG-DLC  102  that services a multi-subscriber facility  120 . The multi-subscriber facility  120  may include an office building, a multi-family dwelling, or other building in which a number of subscribers receive broadband services. Within the multi-subscriber facility  120 , a plurality of subscribers  121  and  122  along with their respective WBAPs  131  and  132  are recipients of broadband services. In the multi-subscriber facility context, the WBAP wireless access regions may overlap significantly, thereby providing improved SNR within large portions, if not all, of the entire multi-subscriber facility. Moreover, as will also discussed below, other subscribers may be provided with broadband services without actually being hardwired to the DSL network. Such non-hardwired subscribers may piggyback on the “benevolent” wireless DSL network bandwidth available within the WBAP wireless access regions.  
         [0022]    In the residential context, there is a significant advantage in ensuring a large percentage of the households have a WBAP to ensure dense coverage within the WBAP wireless access region. In a region having a relatively large number of subscribers, the service provider can ensure adequate signal-to-noise by placing a plurality of WBAPs at subscriber locations having a predetermined separation to ensure that total coverage in the region is above a particular threshold.  
         [0023]    [0023]FIG. 2 is a system diagram illustrating another embodiment of a distributed wireless DSL network  200  that is built in accordance with the present invention. A broadband service interface  201  is operable to service a plurality of subscribers. The broadband service interface  201  may be implemented in various configurations as discussed above in connection with FIG. 1. For example, the servicing may be via a digital subscriber line head-end that is communicatively coupled to a CCB. Alternatively, the service may be provided via a NG-DLC that is operable to provide for broadband service functionality. Moreover, in some embodiments, the service may be provided directly via a central office.  
         [0024]    As shown in FIG. 2, a subscriber  211  and its associated WBAP  221  create a wireless access region  231 . Similarly, a subscriber  212  and its associated WBAP  222  create a WBAP wireless access region  232 , and a subscriber  215  and its associated WBAP  225  create a WBAP wireless access region  235 . The WBAP wireless access regions  231 ,  232 , and  235  are illustrated in FIG. 2 with some degree of overlap. These regions of overlap define areas of enhanced coverage because of an increased signal-to-noise ratio (SNR) introduced by spatial diversity. For example, there are regions where two of the WBAP wireless access regions  231 ,  232 , or  235  overlap with one another, providing increased SNR therein. In addition, there is at least one area where the three WBAP wireless access regions  231 ,  232 , and  235  all overlap with one another (triple overlap) providing significantly increased SNR within that region.  
         [0025]    Similar to the manner in which the overlap of WBAP wireless access regions provide for increased SNR, the principle of overlap can also provide for significantly improved SNR in a multi-subscriber facility  210 . The multi-subscriber facility  210  includes at least a subscriber  213 , with its associated WBAP  223  and a subscriber  214  with its associated WBAP  224  that each provide for a WBAP wireless access region  233  and a WBAP wireless access region  234 , respectively. The regions where these WBAP wireless access regions overlap provide for increased SNR therein.  
         [0026]    [0026]FIG. 3 is a system diagram illustrating another embodiment of a distributed wireless DSL network  300  that is built in accordance with the present invention. A broadband service interface  301  is operable to service a plurality of subscribers. The broadband service interface  301  can be implemented using various combinations of the system components described herein. For example, the service may be provided via a digital subscriber line head-end that is communicatively coupled to a CCB. Service may also be provided via a NG-DLC that is operable to provide for broadband service functionality. Alternatively, service may be provided directly via a central office.  
         [0027]    A subscriber  321  and its associated WBAP  311  create a WBAP wireless access region  331 . Similarly, a subscriber  322  and its associated WBAP  312  create a WBAP wireless access region  332 . The embodiment of FIG. 3 illustrates a system wherein one or more wireless network users are not hardwired to the DSL network&#39;s infrastructure. These wireless network users are able to access the broadband services via the WBAP access regions  331  and  332  provided by the WBAPs  311  and  312  of the subscribers  321  and  322 , respectively.  
         [0028]    For example, wireless network users  341  and  342  are able to access broadband services within the WBAP access region  331 . Similarly, wireless network users  344 , . . . , and  349  are able to access broadband services within the WBAP access region  332 . A wireless network user  343  can be serviced with broadband access using both regions, i.e., the WBAP access regions  331  and  332 . Thus, the two WBAP access regions  331  and  332  provide for a situation where the wireless network user  343  is serviced with broadband access via both the WBAPs  311  and  312 . The embodiment again shows that each subscriber within the distributed wireless DSL network  300  need not be hardwired to the system&#39;s infrastructure. In fact, a large number of users can be serviced using the wireless network, provided that there are a sufficient number of WBAPs in the region. The WBAPs are also implemented so as to accommodate increased numbers of wireless network users including downstream broadcast and upstream data block assembly from among a number of users.  
         [0029]    [0029]FIG. 4 is a system diagram illustrating another embodiment of a distributed wireless DSL network  400  that is built in accordance with the present invention. Again, a broadband service interface  401  is operable to service a plurality of subscribers. The broadband service interface  401  can be implemented using various combinations of the system components described herein. For example, the service may be provided via a digital subscriber line head-end that is communicatively coupled to a CCB. Service may be provided via a NG-DLC that is operable to provide for broadband service functionality. Alternatively, service may be provided directly via a central office.  
         [0030]    The broadband service interface  401  is communicatively coupled to a number of service areas. For example, the broadband service interface  401  communicatively couples to a service area  451  having substantially complete wireless DSL network coverage. The service area  451  is serviced using a WBAP wireless access region created by subscribers and the associated WBAPs. In the system illustrated in FIG. 4, the WBAP wireless access region is generated by a subscriber  411  and the associated WBAP  421 , subscriber  412  and the associated WBAP  422 , and subscriber  413  and the associated WBAP  423 . Each of the WBAPs  421 ,  422 , and  423  provides service to WBAP wireless access regions that cooperatively operate to provide nearly complete wireless DSL network coverage to the entire service area  451 .  
         [0031]    There may be another service area  452  where there is, in fact, complete wireless DSL network coverage because there is a sufficient number of WBAPs operating cooperatively to provide wireless DSL network coverage to the entire service area  452 . There may be another service area  453  where there is only partial wireless DSL network coverage because there is a relatively low number of WBAPs. The embodiment of the FIG. 4 illustrates, among other things, that as the number of WBAPs is increased within a service area, the total wireless DSL network coverage is significantly increased. The wireless DSL network coverage depends on the number and proximity of the WBAPs within the service area.  
         [0032]    [0032]FIG. 5 is a system diagram illustrating an embodiment of a RAKE receiver  520  implemented within a distributed wireless DSL network  500 . The RAKE receiver  520  is comprised of an RF circuit  513 , a pulse shaping circuit  524 , a despreader circuit  522  and an adder  530 . While the function of the various system components in a RAKE receiver are well known to those skilled in the art, the following discussion will briefly summarize operation of a RAKE receiver as it applies to the present invention.  
         [0033]    The RAKE receiver technique employs a plurality of baseband correlators to individually process several multi-path signal components received by the RF circuit  513 . The correlator outputs are combined to achieve improved communications reliability and performance. Each correlator in a RAKE receiver is referred to as a RAKE-receiver finger. For example, a finger  510  including a code generator  512  and a cross correlator  511  constitutes a RAKE-receiver finger. A base station combines the outputs of its RAKE-receiver fingers non-coherently, i.e., the outputs are added in power. A mobile receiver combines its RAKE-receiver finger outputs coherently, i.e., the outputs are added in voltage. There are at least two methods that may be used to combine the RAKE-receiver finger outputs. One method weighs each output equally and is, therefore, called equal-gain combining. The second method uses the data to estimate weights that maximize the SNR of the combined output. This technique is known as maximal-ratio combining. In practice, it is not unusual for both combining techniques to perform with approximately the same efficiency.  
         [0034]    The RAKE receiver  520  is employed as one solution to separate direct waves from delayed transmission waves received by the RF circuit  513 . Since the delayed waveforms cause interference, a multi-path environment is generally undesirable for receiving signals. In this embodiment, a code division multiple access (CDMA) system is operable to separate channels using codes. Within a multi-path received signal, the direct wave may not be the best signal for performing signal processing. Delayed waves may be synthesized to provide a better signal. A RAKE receiver consists of multiple fingers, with one such finger (the finger  510 ) shown in FIG. 5. The despreading process module  522  separates the paths by calculating the correlation using the cross correlator  511  and the code generator  512 . Signal despreading is performed for each of the fingers  1 - 4  (or more) shown in despreader module  522 . The signal paths are then added together in adder module  530 . The manner in which the RAKE receiver  520  synthesizes the multiple paths is sometimes called multi-path diversity. The implementation of the RAKE receiver  520  within the wireless DSL network provides an opportunity to constructively add the signal powers provided by multiple WBAPs within the wireless DSL network.  
         [0035]    [0035]FIG. 6 is a functional block diagram illustrating an embodiment of a distributed wireless DSL network method  600 . In block  610 , high capacity broadband cabling is extended within a communication system further towards subscribers. This broadband cabling may be extended out to a NG-DLC, to a CCB, or to a HEAD-END that is implemented adjacent to a CCB. The broadband cabling is an effort to extend the reach of broadband services to a point further out, closer to the subscribers within a communication system. The particular type of broadband cabling may take a number of forms, including fiber-optic cabling. For example, the fiber-optic cabling may be extended to an NG-DLC as shown in an optional block  612 . Alternatively, the fiber-optic cabling may be extended to a head-end of a CCB as shown in an optional block  614 .  
         [0036]    Within block  620 , wireless broadband access points (WBAPs) are installed throughout the distributed wireless DSL network. As described in various embodiments above, WBAPs may be installed in a number of various configurations. In certain embodiments, a single WBAP may be installed at the location of every subscriber within the distributed DSL wireless network as shown in block  622 . Alternatively, the distributed DSL wireless network may be partitioned into a number of groups, as shown in block  624 , in which a sufficient number of WBAPs are installed so that total wireless DSL coverage may be provided within the entirety of the region.  
         [0037]    As shown within block  630 , the wireless spectrum of the distributed DSL wireless network is managed within the various service areas. The management may be performed to meet any number of goals. In one situation, the management is performed so that total coverage is ensured as shown in block  632 . In another situation, those particular areas whose wireless DSL coverage is critical are ensured coverage as shown in block  634 .  
         [0038]    [0038]FIG. 7A is a functional block diagram illustrating an embodiment of a distributed wireless DSL network downstream communication method  700  that is performed in accordance with the present invention. The downstream broadcast of the distributed wireless DSL network may be performed using code division multiple access (CDMA). In block  710 , common data signals are broadcast downstream from a DSL head-end to wireless broadband access points (WBAPs) at the subscriber(s). Then, in block  720 , customer premises equipment (CPE), dedicated for individual groups/neighborhoods of subscriber(s), extract the appropriate data for those subscriber(s). Then, in block  730 , the CPE forwards that data onto those subscriber(s). Finally, in block  740 , the appropriate subscriber(s) receive and process the appropriate data.  
         [0039]    [0039]FIG. 7B is a functional block diagram illustrating an embodiment of a distributed wireless DSL network upstream communication method  705  that is performed in accordance with the present invention. In block  715 , an individual subscriber transmits data upstream to customer premises equipment (CPE). The operations in the block  715  may be performed upstream to the particular WBAP that services that particular subscriber. Then, in block  725 , within the CPE, the data blocks (that may be referred to as sub-blocks of a frame) for each of the subscriber(s) are assembled into a data block for continued upstream transmission to the DSL head-end. In block  735 , a fragmented frame is assembled using the data blocks for the subscriber(s) provided by the appropriate CPE(s). Finally, in block  745 , the now assembled, fragmented frame is transmitted to the DSL head-end.  
         [0040]    In view of the above detailed description of the invention and associated drawings, other modifications and variations will now become apparent to those skilled in the art. It should also be apparent that such other modifications and variations may be implemented without departing from the spirit and scope of the invention.

Technology Classification (CPC): 7