Abstract:
A wireless network device may receive a first list indicating a first assignment for uplink and downlink time intervals in a time division duplex (TDD) frame and determine at least first downlink time intervals based on the first list. The device may receive a second list indicating a second assignment for uplink and downlink time intervals in a TDD frame and determine at least first uplink time intervals based on the second list. The device may determine at least second downlink time intervals and second uplink time intervals based on a third list, wherein the third list indicates a third assignment for uplink and downlink time intervals in a TDD frame, and wherein the second downlink time intervals include downlink time intervals of at least the first downlink time intervals and the second uplink time intervals include uplink time intervals of at least the first uplink time intervals.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 15/161,990 filed May 23, 2016, which is a continuation of U.S. patent application Ser. No. 14/746,402 filed Jun. 22, 2015, which issued as U.S. Pat. No. 9,350,521 on May 24, 2016, which is a continuation of U.S. patent application Ser. No. 14/337,868 filed Jul. 22, 2014, which issued as U.S. Pat. No. 9,066,341 on Jun. 23, 2015, which is a continuation of U.S. patent application Ser. No. 12/348,637 filed Jan. 5, 2009, which issued as U.S. Pat. No. 8,842,644 on Sept. 23, 2014, which is a continuation of U.S. patent application Ser. No. 11/347,340 filed Feb. 3, 2006, which issued as U.S. Pat. No. 7,474,644 on Jan. 6, 2009, which is a continuation of U.S. patent application Ser. No. 09/910,329 filed July 20, 2001, which issued as U.S. Pat. No. 6,996,078 on Feb. 7, 2006, which claims the benefit of U.S. Provisional Application Ser. No. 60/221,009 filed Jul. 27, 2000, the contents of which are hereby incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to resource allocation in wireless hybrid time division multiple access/code division multiple access communication systems. More specifically, the invention relates to assigning uplink and downlink timeslots in such systems. 
         [0003]      FIG. 1  depicts a wireless communication system. The system has a plurality of base stations  30   1 - 30   11 . Each base station  30   1  communicates with user equipments (UEs)  32   1 ,  32   3 ,  32   4  in its operating area or cell. Communications transmitted from the base station  30   1  to the UE  32   1  are referred to as downlink communications and communications transmitted from the UE  32   1  to the base station  30   1  are referred to as uplink communications. 
         [0004]    In addition to communicating over different frequency spectrums, spread spectrum code division multiple access (CDMA) systems carry multiple communications over the same spectrum. The multiple signals are distinguished by their respective chip codes (codes). To more efficiently use the spread spectrum, some hybrid time division multiple access (TDMA)/CDMA systems as illustrated in  FIG. 2  use repeating frames  34  divided into a number of timeslots  36   1   36   n  such as fifteen timeslots. In time division duplex (TDD) systems using CDMA, a timeslot is used either solely for downlink or uplink communications in a cell. In such systems, a communication is sent in selected timeslots  36   1  - 36   n  using selected codes. Accordingly, one frame  34  is capable of carrying multiple communications distinguished by both timeslot  36   1 - 36   n  and code. The use of a single code in a single timeslot with a spreading factor of sixteen is referred to as a resource unit. Based on a communication&#39;s bandwidth requirements, one or multiple resource units may be assigned to a communication. 
         [0005]    One problem in such systems is cross cell interference as illustrated in  FIG. 3 . A second cell&#39;s base station  30   2  sends a downlink communication  40  to a second cell&#39;s UE  32   2  in a certain timeslot. In the same timeslot, an uplink communication  38  is sent from a first cell&#39;s UE  32   1 . The uplink communication  38  may be received by the first cell&#39;s base station  30   1  at an unacceptable interference level. Although the second cell&#39;s base station  30   2  is further away than the first cell&#39;s UE  32   1 , the higher effective isotopically radiate power (EIPR) of the second cell&#39;s base station  30   2  may result in unacceptable interference at the first cell&#39;s base station  30   1 . 
         [0006]    Also shown in  FIG. 3  is cross interference between UEs  32   1 ,  32   2 . An uplink signal  38  from a first cell&#39;s UE  32   1  will create unacceptable levels of interference to a downlink communication  40  in the same timeslot received by the second cell&#39;s UE  32   2 , due to their close proximity. 
         [0007]    Accordingly, there exists a need for reducing cross cell interference. 
       SUMMARY 
       [0008]    A hybrid time division duplex/code division multiple access communication system comprises a radio network controller coupled to a plurality of Node-Bs. The radio network controller comprises a resource allocation device for providing each Node-B with a list of timeslots that the Node-B can use to assign uplink timeslots and downlink timeslots. The list of timeslots does not include all potential timeslots as being assignable for uplink communications and does not include all potential timeslots as being assignable for downlink communications. Each of the plurality of Node-Bs comprises an assignment device for dynamically assigning uplink and downlink communications to users of the Node-B in response to the assignable uplink and downlink timeslots of the list. 
         [0009]    A method and apparatus for adaptive uplink/downlink resource assignment may include determining uplink interference associated with each of several uplink resources. A wireless network device may produce an uplink list with values for the uplink resources. The device may compare a downlink power level to at least one threshold for each of the downlink resources, wherein at least two of the downlink resources are each associated with a different portion of a frame. The device may produce a downlink list, which may be a bit stream providing an indication, for each downlink resource, indicating whether each of the downlink resources have a downlink power level which is less than or equal to the at least one threshold. The device may send the uplink and downlink lists and may receive an uplink list and a downlink list from each of several neighboring wireless network devices. The device may schedule uplink and downlink resources to a user equipment based on the uplink and downlink lists received. 
         [0010]    A method and apparatus for adaptive uplink/downlink resource assignment may include determining downlink and uplink time intervals for communication. A first wireless network device may receive a first list indicating a first assignment for uplink and downlink time intervals in a time division duplex (TDD) frame and determine at least first downlink time intervals for communication in a TDD frame based on the first list. The device may receive a second list indicating a second assignment for uplink and downlink time intervals in a TDD frame and determine at least first uplink time intervals for communication in a TDD frame based on the second list. The device may determine at least second downlink time intervals and second uplink time intervals for communication in a TDD frame based on a third list, wherein the third list indicates a third assignment for uplink and downlink time intervals in a TDD frame, and wherein the second downlink time intervals include downlink time intervals of at least the first downlink time intervals and the second uplink time intervals include uplink time intervals of at least the first uplink time intervals. Further, the device may communicate, with a second wireless device during at least one TDD frame for communication, in the downlink based on at least the second downlink time intervals. Also, the device may communicate, with a second wireless device during at least one TDD frame for communication, in the uplink based on at least the second uplink time intervals. The third list may dynamically change on a TDD frame basis. The first list and the second list may be received from the second wireless device. Further, each time interval may include at least one time slot. In an example, the first wireless device may receive the third list. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a wireless spread spectrum CDMA system. 
           [0012]      FIG. 2  illustrates timeslots in repeating frames. 
           [0013]      FIG. 3  illustrates cross cell interference. 
           [0014]      FIG. 4  is an availability list. 
           [0015]      FIG. 5  is a flow chart for generating an availability list using base station to base station (BS-BS) and user equipment to user equipment (UE-UE) interference cells. 
           [0016]      FIG. 6  is an example of a cross interference cell list. 
           [0017]      FIG. 7  is a table showing a hypothetical timeslot allocation for each cell. 
           [0018]      FIG. 8  is an availability list for cell  1  constructed using  FIGS. 6 and 7 . 
           [0019]      FIG. 9  is a flow chart for producing an availability list using only BS-BS interference cells. 
           [0020]      FIG. 10  is an illustration of a BS-BS cross interference list. 
           [0021]      FIG. 11  is a flow chart for producing an availability list using only UE-UE interference cells. 
           [0022]      FIG. 12  is a UE-UE cross interference list. 
           [0023]      FIGS. 13 and 14  are flow charts using base station and user equipment interference measurement to determine timeslot availability. 
           [0024]      FIG. 15  is an illustration of a user equipment specific availability list. 
           [0025]      FIGS. 16 and 17  are flow charts for using only interference measurements to determine timeslot availability. 
           [0026]      FIGS. 18, 19 and 20  are flow charts for determining timeslot availability using hybrid approaches. 
           [0027]      FIG. 21  is a flow chart of a timeslot assignment approach. 
           [0028]      FIG. 22  is a flow chart of availability list updating. 
           [0029]      FIG. 23  is the updated table of  FIG. 7 . 
           [0030]      FIG. 24  is an updated availability list for cell  7  based on  FIG. 23 . 
           [0031]      FIG. 25  is a centralized architecture embodiment. 
           [0032]      FIG. 26  is a decentralized architecture embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0033]    Although the following describes timeslot assignment in context of a TDD/CDMA system, the same timeslot elimination procedures and availability lists can be applied to a hybrid TDMA/CDMA system where uplink and downlink communications occur in the same timeslot in a cell. 
         [0034]      FIG. 4  illustrates an availability timeslot list  76 . Along the horizontal axis, each timeslot is listed as S 1 , S 2 , . . . , SN. Along the vertical axis, each cell, listed here by the subscript of its associated base station&#39;s reference number, is listed for both the uplink and downlink. Each row indicates the timeslot availability for either the uplink or the downlink for a cell. Timeslots not available are indicated with an “X”. Available timeslots are left empty. 
         [0035]    One procedure for generating the availability list is shown in  FIG. 5  and is explained in conjunction with  FIGS. 6, 7 and 8 . Initially, the cross interference between each cell pair is measured. Initially, base station  30   1 - 30   11  to base station  30   1 - 30   11  (BS-BS) interfering cells are determined, step  77 . BS-BS interfering cells are cells where a base station&#39;s  30   1 - 30   11  transmissions interfere with another base station&#39;s  30   1 - 30   11  reception. 
         [0036]    Each cell determines its BS-BS interfering cells by estimating interference from the other cells. One approach estimates the BS-BS interfering cells using pre-measured link gains between the base stations  30   1 - 30   11 . If the estimated interference exceeds a threshold, the base stations&#39; cells are considered BS-BS interfering cells, step  77 . Based on the threshold comparison, BS-BS interfering cells are determined and stored in a cross interference cell list  84  as illustrated in  FIG. 6 . The vertical axis of the cross interference cell list  84  has each cell. The horizontal axis has potential cross interfering cells. A cell that BS-BS interferes with another cell is marked in the appropriate box by an “I”, step  79 . For example, since communications in cell  2  cross interfere with cell  1 , the first row, second column box is marked with an “I.” Since a cell does not interfere with itself, these boxes are marked by an “X.” 
         [0037]    Additionally, cells where UEs  32   1 - 32   n  may interfere with other UEs  32   1 - 32   n  are determined, step  78 . Due to the relatively low EIPR of UEs  32   1 - 32   n , the UE-UE interfering cells are in close geographic proximity, such as being adjacent. One UE&#39;s  32   1  uplink transmission can interfere with a neighboring cell&#39;s UE reception, as shown in  FIG. 3 . Since cells with close geographic proximity may have UEs  32   1 - 32   n  which may interfere with each other, these cells are also listed as interfering cells. In  FIG. 6 , the UE-UE interfering cells which were not BS-BS interfering cells are marked with an “I*”, step  79 . 
         [0038]    Using the cross interference cell list  84 , for each cell, the potential cross interference cells are determined, step  78 . For a particular cell in the vertical axis, each cell in the corresponding row marked with an “I” or “I*” is a cross interference cell. For instance, cell  1  is potentially cross interfered by cells  2 ,  3 ,  5 ,  6 ,  9  and  10 . For each cross interference cell, the timeslot allocation is determined. For instance, using the hypothetical timeslot allocation of table  86  of  FIG. 7 , cell  2  is allocated downlink timeslots  1  and  2  and uplink timeslot  9 . For each downlink timeslot allocated in a cross interference cell, a corresponding uplink timeslot is eliminated, step  80 . To illustrate using  FIGS. 6, 7 and 8 , for cell  1 , cell  2 &#39;s allocated downlink timeslot  1  eliminates timeslot  1  from cell  1 &#39;s available uplink timeslots as shown by an “X” in cell  1 &#39;s availability list  88  of  FIG. 8 . 
         [0039]    For each uplink timeslot allocated in a cross interference cell, a corresponding downlink timeslot is eliminated, step  82 . To illustrate for cell  1 , cell  2 &#39;s uplink timeslot  9  eliminates that timeslot from cell  1 &#39;s possible downlink timeslots as shown in cell  1 &#39;s availability list  88 . After eliminating the appropriate timeslots due to the cross interference cells, an availability list  76  for each cell is produced, step  90 . As a result, uplink and downlink timeslots used in cross inference cells are made unavailable reducing cross cell interference. 
         [0040]    To relax the assignment conditions, either only the BS-BS interfering cells or only the UE-UE interfering cells are considered. These approaches may lead to freeing up more resources for each cell. However, the looser criteria may result in unacceptable interference levels with respect to some users. 
         [0041]      FIG. 9  is a flow chart for producing an availability list using only BS-BS interference cells. The BS-BS interference cells are identified, step  122 . A BS-BS cross interference list  132  is produced, such as in  FIG. 10 . If a cell uses a timeslot for the uplink, that slot is eliminated for use by BS-BS interfering cells for the downlink, step  126 . Conversely, if a cell uses a timeslot for the downlink, that slot is eliminated for use by BS-BS interfering cells for the uplink, step  128 . A list of available timeslots is produced for each cell, step  130 . Although this approach more aggressively uses the system&#39;s resources, unacceptable downlink interference may be suffered by some users. 
         [0042]      FIG. 11  is a flow chart for producing an availability list using only UE-UE interference cells. The UE-UE interference cells are identified, step  134 . A UE-UE cross interference list  142  is produced, such as in  FIG. 12 . If a cell uses a timeslot for the downlink, that slot is eliminated for use by UE-UE interfering cells for the uplink, step  136 . Conversely, if a cell uses a timeslot for the uplink, that slot is eliminated for use by UE-UE interfering cells for the downlink, step  138 . A list of available timeslots for each cell is produced, step  140 . This approach may result in unacceptable uplink interference levels for some users. 
         [0043]    Another approach for determining available timeslots uses interference measurements of timeslots, such as by interference signal code power (ISCP). The interference measurements may be taken at the base stations  30   1 - 30   11 , UEs  32   1 - 32   n  or both. 
         [0044]      FIG. 13  is a flow chart using base station and UE interference measurements to determine available timeslots for each UE  32   1 - 32   n . For a particular cell, the interference level in each timeslot is measured at the base station  30   1 , step  144 . Each of the cell&#39;s UEs  32   1 ,  32   3 - 32   4  also measure interference levels in each timeslot, step  146 . The timeslot interference measurements by the base stations are used to determine the availability of uplink timeslots. The downlink timeslot availability is determined on a UE by UE basis (UE specific basis). 
         [0045]    For the uplink, if the base station&#39;s measured interference exceeds a threshold in a timeslot, that timeslot is eliminated for the uplink, step  148 . For the downlink, each UE  32   1 ,  32   3 ,  32   4  eliminates downlink timeslots for its use, if that UE&#39;s interference measurement exceeds a threshold, step  150 . An availability list  154  is produced showing the available uplink timeslots and the available downlink timeslots for each UE as illustrated in  FIG. 15 , step  152 . 
         [0046]    Although two cells are adjacent, the location of specific UEs  32   1 - 32   n  in the cells may be distant. To illustrate using  FIG. 1 , cell  1  and cell  2  are adjacent. However, a UE  32   4  is distant from cell  2 . Accordingly, if UE  32   2  in cell  2  uses a slot for uplink, it will most likely not interfere with the downlink reception of UE  32   4 . However, UE  32   2  uplink transmissions would likely interfere with UE  32   1  downlink transmissions. As a result, a more aggressive resource allocation is available using a UE specific availability list  154 . One drawback is the increased signaling required. Due to UE mobility and other cells&#39; reassignments, the interference measurements must be updated and signaled to the base station  30   1 - 30   11  on a frequent basis. 
         [0047]      FIG. 14  is a flow chart using base station and UE interference measurements to determine non-UE specific available timeslots. The base station  30   1  measures the interference in each timeslot, step  144 , and so does each UE  32   1 ,  32   3 ,  32   4 , step  146 . For the uplink, if the base station measured interference exceeds a threshold in a timeslot, that timeslot is eliminated, step  148 . For the downlink, if any of that cell&#39;s UEs measured interference in a timeslot exceeds the threshold, that timeslot is eliminated for the downlink, step  156 . Using the eliminated timeslots, an availability list  88  for each cell is produced, such as per  FIG. 8 . Since the UE measurements are effectively combined, missing UE interference measurements are not critical to resource unit assignment. 
         [0048]      FIGS. 16 and 17  are flow charts using only UE interference measurements to determine available timeslots. In a cell, each UE measures the interference in each timeslot, step  160 . For the uplink, if any UE interference measurement exceeds the threshold, that timeslot is eliminated for the uplink, step  160 . Alternately, to reduce the number of eliminated uplink timeslots, only the timeslots where most of the UEs have unacceptable interference are eliminated from the uplink, step  160 . If only a few UEs report unacceptable interference, it is assumed these UEs are at the fringe of the cell and are not representative of the overall cell conditions. 
         [0049]    Using a UE specific assignment approach as in  FIG. 16 , each UE  32   1 ,  32   3 ,  32   4  has its own set of available downlink timeslots, such as per  FIG. 15 . For each UE  32   1 ,  32   3 ,  32   4 , a downlink timeslot is eliminated, if that UE interference measurement on the timeslot exceeds a threshold, step  164 . A UE specific availability list  150  is produced, step  166 . 
         [0050]    A non-UE specific approach is shown in  FIG. 17 . If any UE or most UEs&#39; interference measurement exceeds a threshold in the timeslot, that timeslot is eliminated for the downlink, step  168 . An availability list  88 , such as in  FIG. 8 , is produced for the entire cell. 
         [0051]      FIGS. 18, 19 and 20  are timeslot availability determination approaches, using hybrid BS-BS interference, UE-UE interference and interference measurement approaches.  FIGS. 18 and 19  use BS-BS interference cells and UE interference measurements. The BS-BS interfering cells are determined, step  172 . Each UE  32   1 ,  32   3 ,  32   4  measures the interference in each timeslot, step  174 . For the uplink, timeslots are eliminated, if a BS-BS interfering cell uses it for the downlink, step  176 . 
         [0052]    Downlink availability is determined on a UE by UE or a collective basis. Using a UE by UE basis per  FIG. 18 , each UE  32   1 ,  32   3 ,  32   4  compares each timeslot interference measurement to a threshold. If a timeslot measurement exceeds the threshold, that timeslot is eliminated for that UE  32   1 ,  32   3 ,  32   4  in the downlink, step  178 . A UE specific availability list  150 , such as  FIG. 15 , is produced, step  180 . 
         [0053]    Using a collective basis per  FIG. 19 , if any UE timeslot interference measurement exceeds a threshold, that timeslot is eliminated for the downlink for the cell, step  182 . An availability list  88 , such as  FIG. 8 , is produced, step  184 . 
         [0054]      FIG. 20  uses UE-UE interference cells and base station interference measurements. A cell&#39;s base station  30   1  measures the interference levels in each timeslot, step  186 . UE-UE interfering cells are identified, step  188 . For the uplink, eliminate uplink timeslots, if that timeslot&#39;s interference exceeds a threshold, step  190 . For the downlink, a downlink timeslot is eliminated, if a UE-UE interfering cell uses it for the uplink, step  192 . Based on the eliminated timeslots, an availability list  88 , such as  FIG. 8 , is produced. 
         [0055]    For sectored cells, the cross interference list and availability lists  84  are constructed for each sector within the cells. The cross interference between all cell&#39;s sectors is determined. Although the following discussion focuses on non-sectorized cells, the same approach also applies to sectorized cells where the assigning is performed on a per sector basis instead of a per cell basis. 
         [0056]    Using the availability list  76 , each base station  30   1 - 30   n  is assigned timeslots to support its communications using the procedure of  FIG. 21 . Initially, a request for an additional allocated timeslot or timeslots is made, step  92 . Referring to that base station&#39;s availability list  76 , corresponding available timeslots are assigned. To illustrate using the availability list  88  of  FIG. 8 , the base station  30   1  requires both an additional allocated downlink and an uplink timeslot. The available uplink timeslots are slots  4  and  7 - 16  and the available downlink timeslots are slots  1 - 3 ,  5 ,  6 ,  8 ,  10 - 13  and  16 . One uplink timeslot and downlink timeslot will be assigned out of the corresponding available downlink and uplink timeslots. If a UE specific availability list  150  is used, the downlink assignment is based on the UE  32   1 - 32   n  requiring the downlink resource unit(s). 
         [0057]    Since the base stations  30   1 - 30   n  need to dynamically assign and release timeslots due to varying uplink/downlink demand, the information in the availability list  76  requires updating. For approaches using interference measurements, the updates are performed by updating the measurements and the lists. 
         [0058]    For BS-BS and UE-UE approaches, this procedure is shown in  FIG. 22 . Initially, the cross interference cells are identified for each assigned or released timeslot, step  96 . For each assigned downlink timeslot, the corresponding timeslots in the cross interference cells are eliminated for the uplink, step  98 . Conversely, if the uplink timeslot is assigned, the corresponding timeslots in the cross interference cells for the downlink are eliminated, step  100 . To illustrate using  FIGS. 23 and 24 , the base station  30   6  associated with cell  6  assigns timeslot  7  for the downlink, “D*”, and timeslot  8  for the uplink, “U*”, as indicated in table 106 of  FIG. 23 . The cross interference cells are cells  1 ,  2 ,  5  and  7 . As shown for cell  7 &#39;s availability list  107  of  FIG. 24 , timeslot  7  is eliminated for the uplink and timeslot  8  is eliminated for the downlink, both marked as “X*”. 
         [0059]    If a downlink timeslot was released, the corresponding timeslots in the cross interference cells are freed for the uplink unless unavailable for other reasons, such as being used as a downlink timeslot in another cross interference cell, step  102 . For instance, if timeslot  6  of cell  6  is released as indicated in table  106  as “D**”, cell  1 &#39;s uplink timeslot  6  is not made available. Cell  9  is a cross interference cell to cell  1 , which also uses downlink timeslot  6 . By contrast, for cell  7 , the release of downlink timeslot  6  frees the cell for uplink communications as shown in cell  7 &#39;s availability list  108  by an “R.” If an uplink timeslot was released, the corresponding timeslots in the cross interference cells are freed for the downlink unless unavailable for other reasons, step  104 . 
         [0060]    One approach for using uplink/downlink timeslot assignment is shown in  FIG. 25  using a centralized architecture. The radio network controller (RNC)  110  has a resource allocation device  11  to assign or release a timeslot based on user demand. If assigning, the resource allocation device  116  in the RNC  110  assigns an appropriate timeslot using availability list  76 , stored in its memory  117 , per the procedure of  FIG. 21 . The selected timeslots and channel codes are communicated to the base station  30   1 - 30   N  and UEs  32   1 - 32   N , via the node-B timeslot assignment and release device  112   1 - 112   n . If releasing a timeslot, the RNC resource allocation device  116  releases that timeslot and updates the availability list  76 . Accordingly, updating of the availability list  76  is centralized by occurring at the RNC  110 . 
         [0061]    Another approach for uplink/downlink timeslot assignment is shown in  FIG. 26  using a decentralized architecture. Each node-B  122   1 - 122   N  has its own timeslot controller  120   1 - 120   n . When a timeslot assignment and release device  112   1 - 112   n  requests timeslots for a communication, the node-B&#39;s timeslot controller  120   1 - 120   n  selects an appropriate timeslot from its availability list  76 , as stored in its memory  121   1 . The stored availability list  76  to reduce its size may only contain the available timeslots for that node-B&#39;s cell(s). Conversely, the stored availability list  76  may contain the availability for all the RNC&#39;s cells. The decentralized approach allows for faster updates. 
         [0062]    The selected timeslot is assigned to the communication by the timeslot assignment and release device  112   1 - 112   n . To update the lists  76 , that node-B  122   1 - 122   n  updates its list  76 . The assigned and released timeslots are also sent to the RNC  110 . The RNC  110  directs the appropriate timeslot update information to the other cells. The timeslot information either contains an updated availability list  76  or merely the changes to the list  76 . If only the changes are sent, each cell&#39;s controller  120   1 - 120   n  updates its own availability list  76  with that information. The type of timeslot information sent is based on the processing and signaling requirements of the system. 
         [0063]    Assigning uplink/downlink timeslots is adaptable to systems supporting differing signaling rates. For systems supporting only slow network signaling, the allocated timeslot information is updated on a daily basis using a statistical analysis of the uplink/downlink demand. Since communication traffic varies during the day, a faster update rate performs better and is preferred. For medium speed network signaling, the updating is performed periodically ranging from a fraction of an hour to several hours. Medium speed network signaling also uses statistical analysis but over a shorter time period. For fast network signaling, the allocated timeslots are updated on a per call basis or frame basis. Once a timeslot is assigned or released, the appropriate lists are updated. The fast network signaling allocates timeslots on an as needed basis. As a result, it more efficiently uses the system&#39;s resources.