Abstract:
A method is provided for making a quality determination for a plurality of signal channels in an ultrawide bandwidth local network that will not require a coordinator associated with the network to suspend network operation. This is achieved by having the coordinator send a channel quality request to a non-coordinator device in the network. This non-coordinator device then performs a channel quality determination to determine channel quality information about the plurality of signal channels. After it has completed the channel quality determination, the non-coordinator device then sends the channel quality information from the non-coordinator device to the coordinator device. And if the non-coordinator device can accomplish the channel quality determination quickly enough, it need not even remove itself from the network, even temporarily.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present document claims the benefit of the earlier filing date of commonly owned, co-pending U.S. provisional patent application Serial No. 60/380,835, filed May 17, 2002, entitled METHOD OF REMOTE SCANNING, the contents of which are incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to wireless personal area networks and wireless local area networks. More particularly, the present invention relates to systems, methods, devices, and computer program products for allowing a wireless network coordinator to determine the status of a plurality of available channels without temporarily shutting down the network. Even more particularly, the present invention relates to systems, methods, devices, and computer program products for allowing an ultrawide bandwidth wireless network coordinator to determine the status of a plurality of available channels.  
           [0003]    The International Standards Organization&#39;s (ISO) Open Systems Interconnection (OSI) standard provides a seven-layered hierarchy between an end user and a physical device through which different systems can communicate. Each layer is responsible for different tasks, and the OSI standard specifies the interaction between layers, as well as between devices complying with the standard. One possible implementation of the OSI standard is in wireless ultrawide bandwidth (UWB) communications.  
           [0004]    [0004]FIG. 1 shows the hierarchy of the seven-layered OSI standard. As seen in FIG. 1, the OSI standard 100 includes a physical layer  110 , a data link layer  120 , a network layer  130 , a transport layer  140 , a session layer  150 , a presentation layer  160 , and an application layer  170 .  
           [0005]    The physical (PHY) layer  110  conveys the bit stream through the network at the electrical, mechanical, functional, and procedural level. It provides the hardware means of sending and receiving data on a carrier. The data link layer  120  describes the representation of bits on the physical medium and the format of messages on the medium, sending blocks of data (such as frames) with proper synchronization. The networking layer  130  handles the routing and forwarding of the data to proper destinations, maintaining and terminating connections. The transport layer  140  manages the end-to-end control and error checking to ensure complete data transfer. The session layer  150  sets up, coordinates, and terminates conversations, exchanges, and dialogs between the applications at each end. The presentation layer  160  converts incoming and outgoing data from one presentation format to another. The application layer  170  is where communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified.  
           [0006]    The IEEE 802 Committee has developed a three-layer architecture for local networks that roughly corresponds to the physical layer  110  and the data link layer  120  of the OSI standard 100. FIG. 2 shows the IEEE 802 standard 200.  
           [0007]    As shown in FIG. 2, the IEEE 802 standard 200 includes a physical (PHY) layer  210 , a media access control (MAC) layer  220 , and a logical link control (LLC) layer  225 . The PHY layer  210  operates essentially as the PHY Layer  110  in the OSI standard 100. The MAC and LLC layers  220  and  225  share the functions of the data link layer  120  in the OSI standard  100 . The LLC layer  225  places data into frames that can be communicated at the PHY layer  210 ; and the MAC layer  220  manages communication over the data link, sending data frames and receiving acknowledgement (ACK) frames. Together the MAC and LLC layers  220  and  225  are responsible for error checking as well as retransmission of frames that are not received and acknowledged.  
           [0008]    [0008]FIG. 3 is a block diagram of a wireless network  305  that could use the IEEE 802 standard 200, specifically the proposed IEEE 802.15.3 standard. In a preferred embodiment the network  305  is a wireless personal area network (WPAN), or piconet. However, it should be understood that the present invention also applies to other settings where bandwidth is to be shared among several users, such as, for example, wireless local area networks (WLAN), or any other appropriate wireless network.  
           [0009]    When the term piconet is used, it refers to a network of devices connected in an ad hoc fashion, having one device act as a coordinator (i.e., it functions as a master) while the other devices follow the instructions of the coordinator (i.e., they function as clients). The coordinator can be a designated device, or simply one of the devices chosen to function as a coordinator. In any piconet, every non-coordinator device  221 - 225  that is associated must be able to hear a beacon sent out by the coordinator  310 . Consequently, every non-coordinator device  321 - 325  must be able to communicate with the coordinator  310 , but not necessarily with each other.  
           [0010]    As shown in FIG. 3, the network  305  includes a coordinator  310  and a plurality of non-coordinator devices  321 - 325 . The coordinator  310  serves to coordinate the operation of the network  305 . As noted above, the system of coordinator  310  and non-coordinator devices  321 - 325  may be called a piconet, in which case the coordinator  310  may be referred to as a piconet coordinator (PNC). Each of the non-coordinator devices  321 - 325  must be connected to the coordinator  310  via primary wireless links  330 , and may also be connected to one or more other non-coordinator devices  321 - 325  via secondary wireless links  340 . Each non-coordinator device  321 - 325  of the network  305  may be a different wireless device, for example, a digital still camera, a digital video camera, a personal data assistant (PDA), a digital music player, or other personal wireless device.  
           [0011]    In some embodiments the coordinator  310  may be the same sort of device as any of the non-coordinator devices  321 - 325 , except with the additional functionality for coordinating the system and the requirement that it every non-coordinator device  321 - 325  be able to hear the coordinator  310  at the appropriate time. In other embodiments the coordinator  310  may be a separate designated control device.  
           [0012]    The various non-coordinator devices  321 - 325  are confined to a usable physical area  350 , which is set based on the extent to which the coordinator&#39;s  310  beacon can successfully be heard by each of the non-coordinator devices  321 - 325 . Any non-coordinator device  321 - 325  that is able to receive the coordinator&#39;s beacon and is able to communicate with the coordinator  310  (and vice versa) is within the usable area  350  of the network  305 . As noted, however, it is not necessary for every non-coordinator device  321 - 325  in the network  305  to communicate with every other non-coordinator device  321 - 325 .  
           [0013]    [0013]FIG. 4 is a block diagram of a coordinator  310  or a non-coordinator device  321 - 325  from the network  305  of FIG. 3. As shown in FIG. 4, each coordinator  310  or non-coordinator device  321 - 325  includes a physical (PHY) layer  410 , a media access control (MAC) layer  420 , a set of upper layers  430 , and a management entity  440 .  
           [0014]    The PHY layer  410  communicates with the rest of the network  305  via a primary or secondary wireless link  330  or  340 . It generates and receives data in a transmittable data format and converts it to and from a format usable through the MAC layer  420 . The MAC layer  420  serves as an interface between the data formats required by the PHY layer  410  and those required by the upper layers  430 . The upper layers  205  include the functionality of the non-coordinator device  321 - 325 . These upper layers  430  may include TCP/IP, TCP, UDP, RTP, IP, LLC, 1394, USB or the like.  
           [0015]    Typically, the coordinator  310  and the non-coordinator devices  321 - 325  in a WPAN share the same bandwidth. Accordingly, the coordinator  310  coordinates the sharing of that bandwidth. Standards have been developed to establish protocols for sharing bandwidth in a wireless personal area network (WPAN) setting. For example, the IEEE standard 802.15.3 is being developed to provide a specification for the PHY layer  410  and the MAC layer  420  in such a setting where bandwidth is shared using time division multiple access (TDMA). Using this standard, the MAC layer  420  defines frames and super-frames through which the sharing of the bandwidth by the non-coordinator devices  321 - 325  is managed by the coordinator  310  and/or the non-coordinator devices  321 - 325 .  
           [0016]    [0016]FIG. 5 illustrates an exemplary structure of a series of super-frames having a plurality of time slots during a contention free period according to a conventional method of operation. As shown in FIG. 5, the data transmission scheme includes transmitting successive super-frames  550  in time across the network  300 . Each super-frame  550  includes a beacon frame  560 , an optional contention access period (CAP)  570 , and a channel time allocation period (CTAP)  580 . The channel time allocation period  580  includes one or more time slots  590 . These can be guaranteed time slots (GTSs), management time slots (MTSs), or other types of time slots, as desired by the network operation.  
           [0017]    The super-frame  550  itself is a fixed time construct that is repeated in time. The specific duration of the super-frame  550  is described in the beacon frame  560 . In actuality the beacon frame  560  includes information regarding how often the beacon  560  is repeated, which effectively corresponds to the duration of the super-frame  550 . The beacon  560  also contains information regarding the network  300  and the identity of the coordinator  310 .  
           [0018]    In operation, the coordinator  310  uses the beacon  560  to define and assign the time slots  590 . All non-coordinator devices  321 - 325  listen to the coordinator  310  during the beacon period  560 . Each non-coordinator device  321 - 325  will receive zero or more time slots  590 , being notified of each start time and duration from the coordinator  310  during the beacon period  560 . This beacon information uses what is often called TLV format, which stands for type, length, and value. As a result, each device knows when to transmit and when to receive. The beacon period  560 , therefore, is used by the coordinator to coordinate the transmitting and receiving of the non-coordinator devices  321 - 325 .  
           [0019]    The coordinator  310  sends the beacon  560  to all of the non-coordinator devices  321 - 325  at the beginning of each super-frame  550 . The beacon  560  tells each non-coordinator device  321 - 325  the duration or super-frame  550  as well as other information about its MAC address, e.g., the size and duration of the contention access period  570 , if any, and the duration of the channel time allocation period  580 .  
           [0020]    Each beacon  560  will contain information that is not precisely a channel time allocation (CTA). One piece of information will define the beacon period  560  and describe the start time and the duration for the beacon period  560 . Another will define the contention access period  570 , if any, and describe the start time and the duration for the channel time allocation period  570 . Each beacon can also have multiple CTAs. There will be a CTA for each of the time slots  590 . Using dynamic time slots  590 , the slot assignments can change every super-frame with modified CTAs.  
           [0021]    The network can pass control and administrative information between the coordinator  310  and the various non-coordinator devices  321 - 325  through the contention access period  570  or during a management time slot. For example, this can involve information about new devices that want to join the network  300 .  
           [0022]    If a new device  321 - 325  desires to be added to the network  300 , it requests entry from the coordinator  310  in the contention access period  330  or during an association management time slot.  
           [0023]    Individual devices then transmit data packets during the channel time allocation period  480 . The devices  310 ,  321 - 325  use the time slots  490  assigned to them to transmit data packets to other devices (which may include the coordinator  310  if the coordinator  310  is also a device  321 - 325  within the network  300 ). Each device  310 ,  321 - 325  may send one or more packets of data, and may request an immediate acknowledgement (ACK) frame from the recipient device  310 ,  321 - 325  indicating that the packet was successfully received, or may request a delayed (grouped) acknowledgement. If an immediate ACK frame is requested, the transmitting device  310 ,  321 - 325  should allocate sufficient time in the time slot  490  to allow for the ACK frame to arrive.  
           [0024]    It is necessary to organize which devices  310 ,  321 - 325  will be transmitting and which will be listening to avoid collisions of transmitted data. For example if device one  321  and device four  324  both try and transmit data at the same time, this data may collide and cause the receiving devices to fail in acquiring and receiving the signal.  
           [0025]    The reason we allocate individual time slots  590  in the super-frame  550  is because when a given device, e.g., device one  321 , is transmitting to another device, e.g., device five  325 , it&#39;s really broadcasting its signal to everyone, i.e., broadcasting on the open air where anyone who happens to be listening can hear. We would prefer that while device one  321  was transmitting, device five  325  was the only device that was listening. This is basically a TDMA approach. Since the broadcast medium is wireless, when one device is transmitting the system has to limit who else can use the channel.  
           [0026]    Since each particular device  310 ,  321 - 325  knows its transmit start time and duration from information received during the beacon period  560 , each device  310 ,  321 - 325  can remain silent until it is its turn to transmit.  
           [0027]    The time slots  590  shown in this embodiment may be of differing sizes. The starting times and durations of the time slots  590  are determined by the coordinator  310  and sent to the non-coordinator devices  321 - 325  in the beacon  560 .  
           [0028]    One problem that can arise in a wireless network is interference, either with other networks, or unrelated interference sources. This interference can reduce the ability of the network  300  to pass information at a desired data rate, or at all. One way to address this issue is to use multiple channels, each of which may have different interference characteristics. When a network  300  is first started, the coordinator  310  can listen to all of the channels and pick the one that is the most clear.  
           [0029]    It therefore becomes necessary for the coordinator to keep track of the quality of the local transmission medium (i.e., the channels), so that it can take appropriate measures should interference get too great.  
           [0030]    In order to determine the quality of all available channels, the coordinator  310  must suspend all network activity and listen to all possible channels. After it has listened to all available channels, the coordinator  310  can then determine which is the best channel to use, based on certain selection criteria (e.g., low noise in the channel or no other networks operating in the same channel).  
           [0031]    Thus, to make a channel quality determination, network activity must be stopped. However, that comes with a price of lost transmission time, which may violate Quality of Service (QoS) requirements in a network. Such QoS requirements may have set bandwidths that must be guaranteed. Furthermore, if a strict timing transmission protocol is used (e.g., TDMA), the network may not be able to halt operations.  
           [0032]    It would therefore be advantageous to provide a way for a coordinator  310  to determine channel quality without temporarily shutting down the network  300 .  
         SUMMARY OF THE INVENTION  
         [0033]    Consistent with the title of this section, only a brief description of selected features of the present invention is now presented. A more complete description of the present invention is the subject of this entire document.  
           [0034]    A feature of the present invention is to determine the quality of multiple available channels in an ultrawide bandwidth network without stopping operation of the network.  
           [0035]    Another feature of the present invention is to have a coordinator in an ultrawide bandwidth wireless network request that a non-coordinator device perform a channel quality determination so that the coordinator can maintain operation of the network.  
           [0036]    Some of these objects are accomplished by way of a method of making a quality determination for a plurality of signal channels in a wireless network. The method may comprise: sending a channel quality request from a coordinator device in the network to a non-coordinator device in the network; performing a channel quality determination at the non-coordinator device to determine channel quality information about the plurality of signal channels; and sending the channel quality information from the non-coordinator device to the coordinator device.  
           [0037]    The step of performing the channel quality determination may be accomplished by having the non-coordinator device monitor each of the plurality of signal channels in turn.  
           [0038]    Each of the plurality of signal channels may have a different carrier frequency, a different center frequency, may operate at a unique CDMA code, or may have a different combination of center frequency and CDMA code.  
           [0039]    The non-coordinator device may suspend normal operation during the step of performing channel quality determination. The non-coordinator device may not participate in communication with the network during the step of performing the channel quality determination.  
           [0040]    The channel quality information may indicate the presence or absence of radio frequency interference in each signal channel. The channel quality information may further indicate the periodicity of any radio frequency interference in each signal channel.  
           [0041]    The wireless network may be an ultrawide bandwidth network.  
           [0042]    Some of these objects are also accomplished by way of a method of making a quality determination for a plurality of signal channels in a first wireless network. This method comprises: sending a channel quality request from a coordinator device in the local network to a non-coordinator device in the network; performing a channel quality determination at the non-coordinator device to determine channel quality information about the plurality of signal channels; and sending the channel quality information from the non-coordinator device to the coordinator device. The channel quality information in this method may indicate the presence or absence of one or more overlapping wireless networks on one or more of the plurality of signal channels.  
           [0043]    The channel quality information may further indicate the identities of any overlapping wireless networks. The channel quality information may also further indicate the presence or absence of radio frequency interference, as well as the periodicity of any radio frequency interference.  
           [0044]    The step of performing the channel quality determination may be accomplished by having the non-coordinator device monitor each of the plurality of signal channels in turn.  
           [0045]    Each of the plurality of signal channels may have a different carrier frequency, a different center frequency, may operate at a unique CDMA code, or may have a different combination of center frequency and CDMA code.  
           [0046]    The first wireless network and any overlapping wireless networks may be ultrawide bandwidth networks. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0047]    A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. In these drawings like reference numerals designate identical or corresponding parts throughout the several views.  
         [0048]    [0048]FIG. 1 is a block diagram of the OSI standard for a computer communication architecture;  
         [0049]    [0049]FIG. 2 is a block diagram of the IEEE 802 standard for a computer communication architecture;  
         [0050]    [0050]FIG. 3 is a block diagram of a wireless network;  
         [0051]    [0051]FIG. 4 is a block diagram of a device or coordinator in the wireless network of FIG. 3;  
         [0052]    [0052]FIG. 5 illustrates an exemplary structure of a series of super-frames having a plurality of time slots during a contention free period; and  
         [0053]    [0053]FIG. 6 is a flow chart showing a process by which a coordinator  310  can determine the channel quality without stopping network operation, according to a preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0054]    In a network with multiple channels, the coordinator  310  of a network  300  preferably has a way of determining the quality of each available channel. This channel quality determination method is preferably used when a network is initially formed. In that situation, the coordinator  310  will make an initial channel quality determination, and based on that initial determination, choose a channel to use for operation.  
         [0055]    In a preferred embodiment, during a channel quality determination, the coordinator  310  will cycle through all of the available channels, listening and measuring them by set criteria (e.g., amount of noise, magnitude or frequency of interfering signals, the number of other networks in operation, etc.). When it has finished examining all of the channels, the coordinator  310  will determine a desired channel to use and will inform existing devices  321 - 325  of the chosen channel. Operation of the network  300  will then commence, using the chosen transmission channel.  
         [0056]    These channels should not be limited to separate carrier frequency channels. In ultrawide bandwidth (UWB) transmissions, the channels could be defined by different center frequencies. In some embodiments the channels can be virtual channels, e.g., defined by the use of a set of CDMA codes, or any other acceptable means of isolating communications between a set of devices. For example, fixed channel time allocations may be used with networks that are dependent upon other networks to create individual channels for the networks. In other embodiments, a combination of channelization methods could be used. For example, in different channels could be defined by a combination of center frequency and CDMA code. However, regardless of how they are formed, each channel is characterized in that it is a way of transmitting signals over the network  300  that will not interfere with signals sent over the other channels.  
         [0057]    As the network continues operation, however, it may be desirable to switch channels. For example, the current channel might begin to experience interference. Or it the network may consider the other channels from time to time to determine if one is of a better quality than the current channel. It may, therefore, be desirable to periodically determine the quality of all of the available channels in the network  300 . And to avoid shutting down the operation of the network  300 , the job of channel quality determination is performed by one of the non-coordinator devices  321 - 325  in the network  300 , not the network coordinator.  
         [0058]    In many networks, multiple devices maintain the ability to determine channel quality. For example, in IEEE 802.15.3 networks, all capable devices are required to be able to scan through a list of channels to either detect a particular network or to create a list of detected networks. In addition, every device in an 802.15.3 network is assumed to have the capability to rate each channel scanned according to whether a channel has detectable RF energy or not.  
         [0059]    Thus, if there are non-coordinator devices  321 - 325  within a network  300  that are capable of performing a channel quality determination, the coordinator  310  may request one of those non-coordinator devices  321 - 325  to perform such a function and report back to the coordinator  310  with the results. The coordinator  310  can then continue with network processing, allowing the requested non-coordinator device  321 - 325  to stop only its own operations while it determines the quality of the existing channels. And in some cases, if the requested non-coordinator device  321 - 325  can perform the channel quality determination quickly enough, it may not have to stop its own operations to any significant degree.  
         [0060]    Once the requested non-coordinator device  321 - 325  provides the channel quality information, the coordinator  310  can determine whether a switch in the current channel is warranted, and if so, what the new channel should be. A more detailed description of this process follows.  
         [0061]    [0061]FIG. 6 is a flow chart showing a process by which a coordinator  310  can determine the channel quality without stopping network operation, according to a preferred embodiment of the present invention.  
         [0062]    As shown in FIG. 6, process  600  begins when the coordinator  310  requests that a particular non-coordinator device  321 - 325  perform a channel quality determination to determine the status of each available channel. (Step  610 )  
         [0063]    The requested non-coordinator device  321 - 325  will then perform a channel quality determination. (Step  620 ) This channel quality determination preferably comprises listening to each of the available channels, and determining the quality of each channel based on a particular set of criteria. Preferably these criteria include (a) whether there is any radio frequency (RF) energy being transmitted over each band, and (b) whether that RF energy (i.e., RF signal) is decodable or not. These criteria may also include the identity of any other networks  300  that are detected to be transmitting, and whether any detected RF energy is periodic or not.  
         [0064]    The channel quality determination may or may not require the requested non-coordinator device  321 - 325  to break off contact with the network  300 . If the requested non-coordinator device  321 - 325  need not remain in constant contact with the network  300 , it may have a set period of time (e.g., an associated timeout period in an 802.15.3 network) during which it can safely be out of contact with the network  300 . In such a case, requested non-coordinator device  321 - 325  may avoid breaking off contact with the network  300  if it finishes the channel quality determination and returns to its network  300  before the set period of time expires.  
         [0065]    After it has completed the quality determination, the requested non-coordinator device  321 - 325  reports the results of the channel quality determination to the coordinator  310 . (Step  630 ) At this point, the requested non-coordinator device  321 - 325  returns to contact with the network  300  (if it ever left) and carries on with its normal processing.  
         [0066]    Based on the results from the remote channel quality determination, the coordinator  310  then determines whether the current channel is satisfactory. (Step  640 ) This may involve considering the quality of the current channel, and the relative quality of all of the other available channels. Any channel that is currently in use by another network  300 , or which is subject to interference from another source, will be more likely to be determined unsatisfactory.  
         [0067]    If the current channel is determined to be satisfactory in step  640 , then network processing continues without any change in the choice of channel used. (Step  650 ) In this case, the coordinator  310  determines that either the current channel is either adequate for the current processing or is the best available channel.  
         [0068]    If the current channel is determined to be unsatisfactory in step  640 , then the coordinator  310  chooses a new channel that has acceptable parameters (Step  660 ), and then instructs the network to switch to the new channel (Step  670 ). If all available channels are determined to be unsatisfactory, then the coordinator  310  preferably performs a set of functions designed to avoid the interference.  
         [0069]    These interference-avoiding functions may include requesting that the current network  300  become a dependent network of another existing network, changing channel time allocations to avoid a periodic interferer, adjusting maximum transmit power or maximum transmit rate, or shut down the network.  
         [0070]    These interference-avoiding functions may also include using a given channel, but avoiding transmission during a periodic interference signal. For example, if an interfering radar periodically provides a high energy pulse  
         [0071]    If the coordinator  310  desires that its network  300  join another network as a dependent network (e.g., a child or neighbor network), it returns to the least unsatisfactory channel containing an interfering network, and issues a request to the coordinator of that network to become a dependent network of that incumbent network. If this request is accepted, then the requesting coordinator informs its previous network devices which channel to switch to and for which network ID to listen. If this request is denied by the incumbent coordinator, the requesting coordinator  310  continues operating its current network  300  and performs another interference-avoiding function.  
         [0072]    In some embodiments the request in Step  610  will be acknowledged by the requested non-coordinator device  321 - 325 ; in others, it will not. Regardless, a timeout period will preferably be established. If the timeout period is passed without the coordinator  310  receiving an acknowledgement or response from the requested non-coordinator device  321 - 325 , then the scan process should be considered a failure, and the coordinator should repeat the request, if necessary. In this case, the coordinator  310  could send the request to the same non-coordinator device  321 - 325 , or to a different non-coordinator device  321 - 325 , depending upon the circumstances.  
         [0073]    In addition, although the above description has described a process for performing a channel quality determinations of all of the available channels, a quality determination of all available channels need not be performed. In alternate embodiments a smaller subset of available channels could be scanned. In some embodiments a request can be made to perform an analysis on only the current channel being used. In this case, it is possible that more detailed information can be provided regarding the quality and parameters of the current channel.  
         [0074]    In general, a channel quality determination preferably involves looking at some or all of the available channels and determining whether there is decodable or non-decodable RF energy being passed on that channel. If decodable energy is found, the analyzing device  321 - 325  will determine the identity of the source of those transmissions so that later communications will be possible between the current network and that interfering network, if necessary. In non-decodable energy is found, the analyzing device  321 - 325  will try and determine the periodicity of the interfering signal so that a later determination can be made as to whether the interfering signal can be avoided in time.  
         [0075]    A specific description of the primitives and requests that can be used to implement the above scheme are disclosed in provisional patent application Serial No. 60/380,385, filed May 17, 2002, entitled METHOD OF REMOTE SCANNING, the contents of which have been incorporated by reference into this application.  
         [0076]    Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. For example, although the examples given are all ultrawide bandwidth network examples, the system and methods disclosed above are equally applicable to other wireless networks. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.