Abstract:
The invention provides a method and system for a wireless transport layer, such as for use in a wireless communication system. In a preferred embodiment, the wireless transport layer includes the capability for instructing customer premises equipment to adjust the physical characteristics on its communication link with the base station controller, and for instructing customer premises equipment to conduct further communications using those new physical characteristics. The wireless transport layer includes a number of provisions for adjusting communication between the base station controller and customer premises equipment in view of the prospect of adjusting physical characteristics for communication between the two end points. The use of a point-to-multipoint wireless channel provides services over a link whose parameters are continuously adapting to current conditions on a per-user basis.

Description:
[0001]    This application hereby incorporates by reference and claims benefit of U.S. application Ser. No. 09/475,642, filed Dec. 30, 1999 (Attorney Docket No. 164.1002.01). 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The application is submitted in the name of the following inventor(s):  
                                                       Inventor   Citizenship   Residence City and State                           Subir VARMA   United States   San Jose, CA           Jean FUENTES   United States   Santa Clara, CA           Khuong NGO   United States   San Jose, CA           Paul TRUONG   United States   San Jose, CA           Reza MAJIDI-AHY   United States   Los Altos, CA                      
 
           [0003]    1. Field of the Invention  
           [0004]    This invention relates to a link layer, such as for use in a wireless communication system.  
           [0005]    2. Related Art  
           [0006]    Wireless communication between a sender and a receiver includes sending information using a wireless communication link, in which the sender modulates information onto a wireless communication channel (such as a frequency band reserved for wireless communication between the sender and the receiver). The receiver demodulates that information from the wireless communication channel, so as to recover the original information.  
           [0007]    One problem with known systems is that physical characteristics of the communication link between the sender and receiver can change substantially over relatively short periods of time. For example, the distance between the sender and receiver can change. In a second example, the equipment used by the sender or receiver (that is the consumer premises equipment) can change. Moreover, these physical characteristics can change independently of each other. As a result, selection of a single set of such physical characteristics can result in relatively ineffective or inefficient communication between the sender and the receiver.  
           [0008]    Accordingly, it would be advantageous to provide a technique for wireless communication, in which physical characteristics of the communication link between sender and receiver can be changed substantially during a single session of communication, that is not subject to the drawbacks of the known art.  
         SUMMARY OF THE INVENTION  
         [0009]    The invention provides a method and system for a wireless transport layer, such as for use in a wireless communication system. In a preferred embodiment, the wireless transport layer includes the capability for instructing customer premises equipment to adjust the physical characteristics on its communication link with the base station controller, and for instructing customer premises equipment to conduct further communications using those new physical characteristics. In several aspects of the invention, as described herein, the wireless transport layer includes a number of provisions, such as adaptive link layer transport services and an advanced TDMA (time division multiple access) protocol. These work together to adjust communication between the base station controller and customer premises equipment in view of the prospect of adjusting physical characteristics for communication between the two end points. The use of a point-to-multipoint wireless channel provides services over a link whose parameters are continuously adapting to current conditions, on a per-user basis.  
           [0010]    The invention provides an enabling technology for a wide variety of applications for communication, so as to obtain substantial advantages and capabilities that are novel and non-obvious in view of the known art. Examples described below primarily relate to a wireless communication system, but the invention is broadly applicable to many different types of communication in which characteristics of the communication link are subject to change. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 shows a block diagram of a system using a new wireless transport layer in a wireless communication system.  
         [0012]    [0012]FIG. 2 shows a timing diagram of a TDMA frame using a new wireless transport layer in a wireless communication system.  
         [0013]    [0013]FIG. 3 shows a process flow diagram of a method for operating a system using a new wireless transport layer in a wireless communication system. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    In the following description, a preferred embodiment of the invention is described with regard to preferred process steps and data structures. Embodiments of the invention can be implemented using general-purpose processors or special purpose processors operating under program control, or other circuits, adapted to particular process steps and data structures described herein. Implementation of the process steps and data structures described herein would not require undue experimentation or further invention.  
         [0015]    Related Application  
         [0016]    Inventions described herein can be used in conjunction with inventions described in the following documents.  
         [0017]    U.S. patent application Ser. No. ______, Express Mail Mailing No. ______, filed the same day in the name of the same inventors, attorney docket number 164.1003.01, titled “Adaptive Point to Multipoint Communication System.” 
         [0018]    Each of these documents is hereby incorporated by reference as if fully set forth herein.  
         [0019]    Lexicography  
         [0020]    The following terms refer or relate to aspects of the invention as described below. The descriptions of general meanings of these terms are not intended to be limiting, only illustrative.  
         [0021]    base station controller—in general, a device for performing coordination and control for a wireless communication cell. There is no particular requirement that the base station controller must be a single device; in alternative embodiments, the base station controller can include a portion of a single device, a combination of multiple devices, or some hybrid thereof.  
         [0022]    communication link—in general, an element for sending information from a sender to a recipient. Although in a preferred embodiment the communication links referred to are generally wireless line of sight point-to-point communication links, there is no particular requirement that they are so restricted.  
         [0023]    customer premises equipment—in general, a device for performing communication processes and tasks at a customer location, and operating in conjunction with the base station controller within a wireless communication cell. There is no particular requirement that the customer premises equipment must be a single device; in alternative embodiments, the customer premises equipment can include a portion of a single device, a combination of multiple devices, or some hybrid thereof.  
         [0024]    physical parameters—in general, with reference to a wireless communication link, a set of characteristics or parameters relating to physical transmission of information on a communication link. For example, physical characteristics can include (a) a symbol transmission rate, (b) a number of payload data bits assigned per symbol, (c) a number of error detection or correction bits assigned per symbol, and the like.  
         [0025]    wireless communication system—in general, a communication system including at least one communication link that uses wireless communication techniques.  
         [0026]    wireless transport layer—in general, a set of protocols and protocol parameters for sending and receiving information using wireless transport. In a preferred embodiment, the wireless transport layer is part of a multilayer systems architecture, in which the wireless transport layer is built using a physical transport layer, and the wireless transport layer is used by a logical transport layer such as IP.  
         [0027]    As noted above, these descriptions of general meanings of these terms are not intended to be limiting, only illustrative. Other and further applications of the invention, including extensions of these terms and concepts, would be clear to those of ordinary skill in the art after perusing this application. These other and further applications are part of the scope and spirit of the invention, and would be clear to those of ordinary skill in the art, without further invention or undue experimentation.  
         [0028]    System Context  
         [0029]    A system using a wireless transport layer in a wireless communication system operates as part of a system in which devices coupled to a network (such as a computer network) send messages, route and switch messages, and receive messages. Most current link layer protocols use a simple “first come, first served” policy for serving these messages. Other systems allow the physical link to be divided into a number of virtual links, each with its own set of bandwidth and QoS parameters. Unlike the existing technology, the device described herein also includes a virtual link that describes a set of physical layer parameters. Thus, in a preferred embodiment, devices coupled to (and integrated with) the network send, route, and receive these messages as sequences of packets, each of which has a header including delivery information and a payload including data. The packet format conforms to the OSI model, in which an application protocol (layer  4 , such as TCP) uses a logical transport protocol (layer  3 , such as IP), which uses a physical transport protocol (layer  2 ), which uses a physical transport technique (layer  1 ).  
         [0030]    The system using a wireless transport layer is described herein with regard to layer  2 , particularly as it applies to interactions with layer  1  and layer  3 . However, concepts and techniques of the invention are also applicable to other layers of the OSI model. Adapting those concepts and techniques to such other layers would not require undue experimentation or further invention, and is within the scope and spirit of the invention.  
         [0031]    System Elements  
         [0032]    [0032]FIG. 1 shows a block diagram of a system using a new wireless transport layer in a wireless communication system.  
         [0033]    A system  100  includes a wireless communication cell  110 , a base station controller  120 , and one or more sets of customer premises equipment  130 .  
         [0034]    The wireless communication cell  110  includes a generally hexagon-shaped region of local surface area, such as might be found in a metropolitan region. Use of generally hexagon-shaped regions is known in the art of wireless communication because they are able to tile a local region with substantially no gaps. However, although in a preferred embodiment the wireless communication cell  110  includes a generally hexagon-shaped region, there is no particular requirement for using that particular shape; in alternative embodiments it may be useful to provide another shape or tiling of the local surface area.  
         [0035]    The base station controller  120  includes a processor, program and data memory, mass storage, and one or more antennas for sending or receiving information using wireless communication techniques.  
         [0036]    Similar to the base station controller  120 , each set of customer premises equipment  130  includes a processor, program and data memory, mass storage, and one or more antennas for sending or receiving information using wireless communication techniques.  
         [0037]    Communication among devices within the wireless communication cell  110  is conducted on one-to-one basis between each set of customer premises equipment  130  and the base station controller  120 . Thus, the base station controller  120  communicates with each set of customer premises equipment  130 , and each set of customer premises equipment  130  communicates with the base station controller  120 . Customer premises equipment  130  do not communicate directly with other customer premises equipment  130 .  
         [0038]    Communication between the base station controller  120  and each set of customer premises equipment  130  is conducted using a time division duplex technique, in which time duration is are divided into individual frames, each one of which includes a “downstream” portion and an “upstream” portion. Unlike existing protocols in which transmissions are controlled by the transmitting side, the base station controller  120  controls tranmissions for both upstream and downstream directions, without specific requests from the customer premises equipment  130 .  
         [0039]    During the downstream portion of each frame, the base station controller  120  transmits, thus sending information to one or more sets of customer premises equipment  130 . During the upstream portion of each frame, the base station controller automatically allocates slots for upstream re-transmission. This occurs in the absence of an explicit request for a slot from the customer premises equipment  130 . Particular aspects of each frame are described with regard to FIG. 2. Time division duplex techniques are known in the art of wireless communication.  
         [0040]    TDMA Frame  
         [0041]    [0041]FIG. 2 shows a timing diagram of a TDMA frame using a new wireless transport layer in a wireless communication system.  
         [0042]    A timing diagram  200  shows a time division multiple access (TDMA) frame  210 , including the downstream portion  220  and the upstream portion  230 . A guard band  240  separates the downstream portion  220  from the upstream portion  230 . In a preferred embodiment, the guard band  240  has a duration at least equal to twice the flight time of a transmission from the base station controller  120  to the most distant customer premises equipment  130  and back.  
         [0043]    Each frame included in a TDMA frame  210  includes a frame descriptor packet  250  that describes the contents of the following frame to each consumer premises equipment  130 . The frame descriptor packet  250  has several constant properties: (1) it is always the first packet in a TDMA frame  210 ; and (2) it is always a fixed size. In addition to these constants, the size of a TDMA frame  210  is also fixed and every TDMA frame always starts at times that are multiples of the frame size. These constant properties ensure that contact between the consumer premises equipment  130  and the base station controller  120  is always maintained, even if one or more frame descriptor packets  230  should get “lost”.  
         [0044]    Each frame included in the downstream portion  220  includes a map section  221 , a synchronization section  222 , and one or more downstream payload elements  223 , all of which are formatted as data packets, complete with packet headers and associated information. An inter-payload guard band  224  separates successive downstream payload elements  223 . In a preferred embodiment, the inter-payload guard band  224  has a duration of sixteen symbols (where the duration of each symbol is responsive to the initial map section  221 ), but in alternative embodiments, the duration may take on other values.  
         [0045]    Each frame in the upstream portion  230  includes one or more request sections  231 , one or more acknowledgment sections  232 , a maintenance section  233 , and one or more upstream payload elements  223  all of which are formatted as data packets, complete with packet headers and associated information. Similar to the downstream portion  220 , an inter-payload guard band  224  separates successive upstream payload elements  223 .  
         [0046]    Unlike existing systems that monitor the number of packets that are transmitted, the system  100  monitors the number of bytes that are transmitted. Thus, the packet sizes included in the upstream and downstream frames can vary without breaking protocol.  
         [0047]    The base station controller  120  directs each set of customer premises equipment  130  to conduct wireless communication using a set of physical parameters and a set of MAC parameters, as selected by the base station controller  120 . Because each set of customer premises equipment  130  is uniquely situated, the base station controller  120  cannot generally determine a single set of physical parameters and MAC parameters to be used by all of the customer premises equipment  130  at once. Accordingly, the base station controller  120  determines the individual physical parameters and individual MAC parameters to be used by each individual set of customer premises equipment  130 . After making each such individual determination, the base station controller  120  constructs a descriptor, for each set of customer premises equipment  130 , of physical parameters and MAC parameters to be used by that set of customer premises equipment  130 . In a preferred embodiment, this descriptor packet pre-announces the new set of parameters to each transmitter or receiver device, thereby allowing them to configure themselves to the new set of parameters. This is very different from existing schemes which embed the parameters in the header of a packet. Embedding the parameters in the header of a packet causes problems because the header always has to be sent using a common set of parameters. Moreover, using a packet header in this way does not allow sufficient time for the transmitter or receiver to re-configure itself for the data payload burst.  
         [0048]    In a preferred embodiment, the physical parameters and MAC parameters that can be tailored by a base station controller  120  include some or all or a combination of the following:  
         [0049]    Symbol rate  
         [0050]    Modulation  
         [0051]    Power  
         [0052]    Polarization  
         [0053]    Antennae  
         [0054]    Forward Error Correction  
         [0055]    Packet Size  
         [0056]    The map section  221  includes, for each set of customer premises equipment  130 , the descriptor of physical parameters and MAC parameters to be used by that set of customer premises equipment  130 .  
         [0057]    The synchronization section  222  is used to synchronize the base station controller  120  clock (not shown) with clocks included in each customer premises equipment  130  (not shown). Each synchronization section  222  includes a set of information (such as an equalizer training sequence) known ahead of time by each set of customer premises equipment  130 . Each set of customer premises equipment  130  is capable of receiving the synchronization section  222  (and therefore the known information in the synchronization section  222 ), and capable of synchronizing its internal clock (not shown) to correspond with a master clock (not shown) at the base station controller  120 . For example, each set of customer premises equipment  130  can include a phase locked loop disposed so as to receive the synchronization section  222  and phase lock the internal clock for that set of customer premises equipment number  130  with the master clock at the base station controller  120 . Thus, each set of customer premises equipment  130  is frequently synchronized with the base station controller  120 . Techniques for synchronization of distributed equipment using wireless communication are known in the art of wireless communication.  
         [0058]    Each downstream payload element  223  includes payload information sent from the base station controller  120  to a specific target set of customer premises equipment  130 . The payload information is separately formatted by the base station controller  120  in response to the physical parameters and MAC parameters for the target customer premises equipment  130 . Thus, each downstream payload element  223  includes a sequence of symbols, each encoding a sequence of bits, separately formatted by the base station controller  120 , transmitted by the base station controller  120 , and thus sent from the base station controller  120  to the target customer premises equipment  130 .  
         [0059]    Those skilled in the art will recognize, after perusal of this application, that each downstream payload element  223  is separately formatted according to an individual set of physical parameters and MAC parameters. Thus, each downstream payload element  223  might have an individual duration, and even when two downstream payload elements  223  have identical duration, might have an individual number of symbols, an individual number of bits per symbol, and an individual number of total bits for the downstream payload element  223 .  
         [0060]    Those skilled in the art will recognize, after perusal of this application, that each downstream payload element  223  is separately received and decoded by its target customer premises equipment  130 , according to the individual set of physical parameters and MAC parameters determined by the base station controller  120  and sent by the base station controller  120  during the map section  221  in the same downstream portion  220  in the same TDMA frame  210 . Thus, the base station controller  120  is able to send information to each set of customer premises equipment  130  and to direct each set of customer premises equipment  130  to receive that information using an optimal set of physical parameters and MAC parameters for that TDMA frame  210 .  
         [0061]    Similarly, the base station controller  120  directs each set of customer premises equipment  130  to conduct communications using the physical parameters and MAC parameters transmitted in the map section  221  of the same TDMA frame  210 . Thus, upstream payload elements  223  sent by each individual set of customer premises equipment  130  are formatted by each individual set of customer premises equipment  130  using the optimal set of physical parameters and MAC parameters (as determined by the base station controller  120 ) for that TDMA frame  210 .  
         [0062]    The request section  231  includes a sequence of requests to transmit up-stream payload elements  223 , as requested by each set of customer premises equipment  130 . The request section  231  is not expressed as a unit of time or a number of packets. The request section  231  specifically requests a number of payload bytes. This is preferable since given that the packets are of variable size, specifying their number does not tell the base station controller  120  about the number of bytes that need to be transmitted. Furthermore, it is not feasible for the consumer premises equipment  130  to make requests in units of transmit time because the link parameters assigned to the consumer premises equipment  130  change over time. The consumer premises equipment  130  sequentially numbers each byte and writes the sequence number of the last byte in its buffer into the request section  231 . In combination with the sequence number of the byte being transmitted, this scheme allows the base station controller  120  to unambiguously estimate the current backlog in the consumer premises equipment  130 .  
         [0063]    The acknowledgment sections  232  each include an acknowledgment message by customer premises equipment  130  not otherwise sending an acknowledgment to the base station controller  120 .  
         [0064]    The maintenance section  233  includes maintenance information transmitted by either the base station controller  120  or by one or more sets of customer premises equipment  130 .  
         [0065]    Similar to the downstream payload elements  223 , the upstream payload elements  223  each includes payload information sent from customer premises equipment  130  to the base station controller  120 . The payload information is separately formatted by each customer premises equipment  130  in response to the physical parameters and MAC parameters determined by the base station controller  120  for the sending customer premises equipment  130  (and transmitted during the map section  221 ). Thus, similar to each downstream payload element  223 , each upstream payload element  223  includes a sequence of symbols, each encoding a sequence of bits, separately formatted by the customer premises equipment  130 , transmitted by the customer premises equipment  130 , and thus sent from the customer premises equipment  130  to the base station controller  120 .  
         [0066]    Method of Operation  
         [0067]    [0067]FIG. 3 shows a process flow diagram of a method for operating a system using a new wireless transport layer in a wireless communication system.  
         [0068]    A method  300  includes a set of flow points and a set of steps. The system  100  performs the method  300 . Although the method  300  is described serially, the steps of the method  300  can be performed by separate elements in conjunction or in parallel, whether asynchronously, in a pipelined manner, or otherwise. There is no particular requirement that the method  300  be performed in the same order in which this description lists the steps, except where so indicated.  
         [0069]    Sending Downstream Information  
         [0070]    At a flow point  310 , the base station controller  120  is ready to send information to one or more sets of customer premises equipment  130 .  
         [0071]    At a step  311 , the base station controller  120  determines sets of physical parameters and MAC parameters it considers optimal for each set of customer premises equipment  130 .  
         [0072]    At a step  312 , the base station controller  120  determines information it will send to each set of customer premises equipment  130 .  
         [0073]    At a step  313 , the base station controller  120  formats the downstream portion  220  of the TDMA frame  210 . As part of this step, the base station controller  120  formats the map section  221 , to include the physical parameters and MAC parameters it determined in the step  311  for each individual set of customer premises equipment  130 . As part of this step, the base station controller  120  formats the synchronization section  222 . As part of this step, the base station controller  120  formats one or more downstream payload elements  223 , to include the information it determined in the step  312  for each individual set of customer premises equipment  130 .  
         [0074]    At a step  314 , the base station controller  120  waits for the guard band  340  to pass before attempting to receive information from customer premises equipment  130 . The method  300  continues with the flow point  330  and the flow point  340 .  
         [0075]    After this step, the base station controller  120  has performed one instance of sending information during the downstream portion  220 . The flow point  310  is reached repeatedly and the steps thereafter are performed repeatedly, for each TDMA frame  210 .  
         [0076]    Receiving Downstream Information  
         [0077]    At a flow point  320 , preferably reached in parallel with the flow point  310 , one or more sets of customer premises equipment  130  are ready to receive information from the base station controller  120 .  
         [0078]    At a step  321 , each individual customer premises equipment  130 , having been earlier synchronized with the base station controller  120 , receives the map section  221 , including the physical parameters and MAC parameters the base station controller  120  considers optimal for communication with that individual of customer premises equipment  130 .  
         [0079]    At a step  322 , each individual customer premises equipment  130  receives the synchronization section  222 , and re-synchronizes its internal clock to correspond with the master clock at the base station controller  120 . Since each individual customer premises equipment  130  can be a different distance from the base station controller  120 , each individual customer premises equipment  130  will receive the synchronization section  222  at a (slightly) different time, and thus each individual customer premises equipment  130  will run its internal clock at a (slightly) different phase from the master clock at the base station controller  120 .  
         [0080]    At a step  323 , each individual customer premises equipment  130  receives one or more downstream payload elements  223 , using the physical parameters and MAC parameters it received during the map section  221 .  
         [0081]    At a step  324 , each individual customer premises equipment  130  waits for the guard band  340  to pass before attempting to send information to the base station controller  120 . The method  300  continues with the flow point  330  and the flow point  340 .  
         [0082]    After this step, each individual customer premises equipment  130  has performed one instance of receiving information during the downstream portion  220 . The flow point  320  is reached repeatedly and the steps thereafter are performed repeatedly, for each TDMA frame  210 .  
         [0083]    Sending Upstream Information  
         [0084]    At a flow point  330 , individual customer premises equipment  130  are ready to send information to the base station controller  120 .  
         [0085]    At a step  331 , each individual customer premises equipment  130  determines whether it desires to request allocation of bandwidth for transmission during the TDMA frame  210 . As part of this step, the individual customer premises equipment  130  formats a request for transmission during a specific request section  231  designated for use by that individual customer premises equipment  130 .  
         [0086]    At a step  332 , each individual customer premises equipment  130  that desires to request allocation of bandwidth for transmission transmits during its assigned request section  231 , so as to inform the base station controller  120  of its desire. For example, individual customer premises equipment  130  might be given a numeric ordering by the base station controller  120 , so that each individual customer premises equipment  130  has an assigned time slot during which it can request bandwidth allocation from the base station controller  120 . Alternatively, individual customer premises equipment  130  might contend for individual request sections  231 , using a “slotted aloha” technique or other known technique for contention for limited resources.  
         [0087]    In a alternative embodiment, the base station controller  120  determines, for each request section  231 , whether that request section  231  will be assigned to a particular customer premises equipment  130 , or will be open for contention like multiple customer premises equipment  130 . In the latter case, the base station controller  120  determines, for those request sections  231  which are open for contention, whether contention will be limited to particular subsets of customer premises equipment  130 , or whether contention will be open to all customer premises equipment  130 .  
         [0088]    When the base station controller  120  receives requests for allocation of bandwidth, the base station controller  120  determines, for the following TDMA frame  210 , the allocations of bandwidth it considers optimal for particular customer premises equipment  130 . The particular allegations determined by the base station controller  120  are transmitted during the next TDMA frame  210 , during the downstream portion  220 , during the map section  221 .  
         [0089]    At a step  333 , each individual customer premises equipment  130  that desires to make an acknowledgment of information is received from the base station controller  120 , transmits during its designed acknowledgment section  232 , so as to inform the base station controller  120  of its acknowledgment. In a preferred embodiment, acknowledgement sections  232  are specifically assigned to individual customer premises equipment  130 .  
         [0090]    In an alternative embodiment, the base station controller  120  determines, for each acknowledgment section  232 , which particular customer premises equipment  130  will have use of that acknowledgment section  232 . Moreover, in a preferred embodiment, individual customer premises equipment  130  having allocations of bandwidth for transmission using upstream payload elements  223  will generally not require further bandwidth for transmission during acknowledgments sections  232 . Accordingly, the base station controller  120  can reserve individual acknowledgment sections  232  for particular customer premises equipment  130  not already having allocations for bandwidth for transmission using upstream payload elements  223 .  
         [0091]    At a step  334 , each individual customer premises equipment  130  determines whether it needs to transmit during the maintenance section  233 . As part of this step, each individual customer premises equipment  130  which has so determined formats information for transmission during the maintenance action  233 , and transmits that information during the maintenance section  233 , so that the base station controller  120  can receive that information.  
         [0092]    At a step  335 , each individual customer premises equipment  130  heading allocations of bandwidth for transmission using upstream payload elements  223  determines what information that individual customer premises equipment intends to send to the base station controller  120 . As part of this step, each individual customer premises equipment  130 , intending to send information to the base station controller  120 , formats information into an upstream payload element  223 , and transmits that upstream payload element  223  during the time assigned for transmission to that individual cost of premises equipment  130 .  
         [0093]    In a preferred embodiment, the base station controller  120  determines, for each time slot possibly allocable for an upstream payload element  223 , which specific individual customer premises equipment  130  is allocated that particular time slot. However, in alternative embodiments, the base station controller  120  might reserve one or more time slots allocable for upstream payload elements  223  for contention among more than one individual customer premises equipment  130 .  
         [0094]    As noted above, each individual customer premises equipment  130  uses the physical parameters and MAC parameters determined by the base station controller  120  for that particular customer premises equipment  130  and transmitted during the map section  221  of the same TDMA frame  210 .  
         [0095]    After this step, each individual customer premises equipment  130  has performed one instance of sending information during the upstream portion  230 . The flow point  330  is reached repeatedly and the steps thereafter are performed repeatedly, for each TDMA frame  210 .  
         [0096]    Receiving Upstream Information  
         [0097]    At a flow point  340 , preferably reached in parallel with the flow point  330 , the base station controller  120  is ready to receive information from one or more sets of customer premises equipment  130 .  
         [0098]    At a step  341 , the base station controller  120  receives information transmitted during each request section  231  by one or more individual customer premises equipment  130 . As part of this step, the base station controller  120  determines whether one or more request sections  231  have been subject to contention (and thus have been unable to be used to send or receive information). As part of this step, the base station controller  120  determines what allocations of bandwidth for transmission it will make for individual customer premises equipment  130  for the following TDMA frame  210 .  
         [0099]    At a step  342 , the base station controller  120  receives information transmitted during each acknowledgment section  232 , by one or more individual customer premises equipment  130 . As part of this step, the base station controller  120  determines which of its downstream payload elements  223  sent to individual customer premises equipment  130  have been acknowledged and therefore have been received properly.  
         [0100]    At a step  343 , the base station controller  120  receives information transmitted during the maintenance section  233 , by one or more individual customer premises equipment  130 . As part of this step, the base station controller  120  determines any maintenance steps it must take in response to such information.  
         [0101]    At a step  344 , the base station controller  120  receives information transmitted during one or more upstream payload elements  223 , by one or more individual customer premises equipment  130 . As part of this step, similar to receipt of individual request sections  231  (and possibly similar to receipt of individual acknowledgment sections  232 ), the base station controller  120  determines whether one or more upstream payload elements  223  have been subject to contention (and thus have been unable to be used to send or receive information).  
         [0102]    In a alternative embodiment, the base station controller  120  parses those upstream payload elements  223  for which it has been able to receive information, and determines whether those upstream payload elements  223  include acknowledgments of downstream payload elements  223  which were sent by the base station controller  122  to individual customer premises equipment  130 . If so, the base station controller  120  treats those acknowledgments which were “piggybacked” onto upstream payload elements  223  in similar manner to acknowledgments received during acknowledgment sections  232 .  
         [0103]    As noted above, the base station controller  120  receives and parses those upstream payload elements  223  using physical parameters and MAC parameters determined by the base station controller  120  for that particular customer premises equipment  130  and transmitted during the map section  221  of the same TDMA frame  210 .  
         [0104]    After this step, the base station controller  120  has performed one instance of receiving information during the upstream portion  230 . The flow point  340  is reached repeatedly and the steps thereafter are performed repeatedly, for each TDMA frame  210 .  
         [0105]    An optional step  345  may occur at any time during the method  300  in response to the frequency of dropped packets. A packet is designated as “dropped” after the method  300  failed to get it across after re-transmitting it several times. In this step, the system  100  changes link parameters if two packets are dropped within a specified number of packet transmissions from each other. This allows the system  100  to tolerate a certain level of dropped packets without being affected. However, if the drop rate exceeds a certain threshold, the link parameters are changed. This approach is very different from existing methods which change link parameters in response to explicit measurements such as the signal-to-interference ratio.  
         [0106]    Generality of the Invention  
         [0107]    The invention has general applicability to various fields of use, not necessarily related to the services described above. For example, these fields of use can include one or more of, or some combination of, the following:  
         [0108]    The invention is applicable to other forms of wireless communication, such as frequency division multiple access (FDMA) or code division multiple access (CDMA, also known as spread spectrum communication);  
         [0109]    The invention is applicable to wireline (that is, non-wireless) communication, in which now can be achieved from dynamically adjusting communication parameters, such as physical parameters or MAC parameters. For example, the invention can be generalized to wireline communication using modems in which equalization parameters are to be dynamically adjusted.  
         [0110]    The invention is applicable to other wireless communication systems, such as satellite communication systems and (microwave tower or other) point to point transmission systems.  
         [0111]    Other and further applications of the invention in its most general form, will be clear to those skilled in the art after perusal of this application, and are within the scope and spirit of the invention.  
         [0112]    Technical Appendix  
         [0113]    A technical appendix enclosed with this application is part of the disclosure of this application, and is hereby incorporated by reference as if fully set forth herein.  
         [0114]    Alternative Embodiments  
         [0115]    Although preferred embodiments are disclosed herein, many variations are possible which remain within the concept, scope, and spirit of the invention, and these variations would become clear to those skilled in the art after perusal of this application.