Method and means for allocating time slots in a TDD system

Abstract

Method and apparatus for allocating time slots in a time division duplex communication system. First and second types of time slots selected from receiving and transmitting type time slots are allocated as the first and second time slots, respectively, in a current frame. Based on an amount of information to be transferred, it is determined whether at least one time slot following the second time slot of the frame should be allocated as the first type of time slot, and if so, the last time slot of the frame is always allocated as the first type of time slot, whereby the last time slot of the frame and the first time slot of a succeeding frame are of the same type. If an additional time slot(s) is allocated for the second type of time slot, the third slot is always designated for the second type.

1. Method of allocating time slots in a time division duplex communication system, in which information is transmitted and received in predetermined time frames each having a predetermined number of time slots, wherein first and second types of time slots selected from receiving and transmitting type time slots are allocated, the first time slot of each frame is allocated as the first type of time slot, and the second time slot of each frame is allocated as the second type of time slot, said method comprising:
 determining, based on an amount of information to be transferred, whether at least one time slot following the second time slot of a current frame should be allocated as the first type of time slot, and if so, always allocating the last time slot of the current frame as the first type of time slot, whereby the last time slot of the current frame and the first time slot of a succeeding frame are the same type of time slots; and  
 allocating time slots following the second time slot of the current frame as additional receiving or transmitting time slots dependent on an amount of information to be transmitted and/or received, wherein if additional time slot(s) are allocated for the second type of time slot, always allocating at least the third time slot of the current frame as an additional second type time slot.  
 
     
     
       2. The method according to  claim 1 , wherein the number of additional receiving time slots and the number of additional transmitting time slots are independent from one another. 
     
     
       3. The method according to the  claim 1 , wherein the first and second time slots of the current frame are receiving and transmitting time slots, respectively, and each is allocated to a first communication unit. 
     
     
       4. The method according to  claim 3 , wherein additional slots are also allocated to the first communication unit. 
     
     
       5. The method according to  claim 3 , wherein one of time frames (F 1 , F 2 , . . . ) is assigned to several communication units and the additional time slots are allocated to communication units different from said first communication unit. 
     
     
       6. The method according to  claim 1 , wherein when both the last time slot and next to last time slot of the current frame are each allocated for transmitting or receiving, a guard period is provided in at least one of said last and next to last time slots. 
     
     
       7. The method according to  claim 6 , wherein said next to last time slot of the current frame is the second type of time slot, said last time slot is the first type of time slot, and said guard period is provided at the end of said next to the last time slot. 
     
     
       8. Apparatus for allocating time slots in a time division duplex communication system, in which information is transmitted and received in predetermined time frames each having a predetermined number of time slots, wherein first and second types of time slots selected from receiving and transmitting type time slots are allocated, the first time slot of each frame is allocated as the first type of time slot, and the second time slot of each frame is allocated as the second type of time slot, said apparatus comprising:
 determining means for determining, based on an amount of information to be transferred, whether at least one time slot following the second time slot of a current frame should be allocated as the first type of time slot, and if so, always allocating the last time slot of the current frame as the first type of time slot, whereby the last time slot of the current frame and the first time slot of a succeeding frame are the same type of time slots; and  
 allocating means for allocating time slots following the second time slot of the current frame as additional receiving or transmitting time slots dependent on an amount of information to be transmitted and/or received, wherein if additional time slot(s) are allocated for the second type of time slot, always allocating at least the third time slot of the current frame as an additional second type time slot.  
 
     
     
       9. Apparatus according to  claim 8 , wherein the number of additional receiving time slots and the number of additional transmitting time slots are independent from one another. 
     
     
       10. Apparatus according to  claim 8 , wherein the first and second time slots of the current frame are receiving and transmitting time slots, respectively, and each is allocated to a first communication unit. 
     
     
       11. Apparatus according to  claim 10 , wherein additional slots are also allocated to the first communication unit. 
     
     
       12. Apparatus according to  claim 10 , wherein one of time frames (F 1 , F 2 , . . . ) is assigned to several communication units and the additional time slots are allocated to communication units different from said first communication unit. 
     
     
       13. Apparatus according to  claim 8 , wherein when both the last time slot and next to last time slot of the current frame are each allocated for transmitting or receiving, a guard period is provided in at least one of said last and next to last time slots. 
     
     
       14. Apparatus according to  claim 13 , wherein said next to last time slot of the current frame is the second type of time slot, said last time slot is the first type of time slot, and said guard period is provided at the end of said next to last time slot. 
     
     
       15. Communication method for transmitting and receiving information in a time division duplex communication system, comprising the steps of:
   allocating a changeable number of receiving time slots and a number of transmitting time slots in a time frame having a predetermined number of time slots, the allocation of time slots being changed when the amount of information to be transferred is changed, and        transmitting information by using said time slots dependent on the amount of information to be transferred,        wherein said time frame contains at least a receiving time slot and an adjacent transmitting time slot, and a guard period provided in at least one of said receiving and adjacent transmitting time slots.     
     
     
       16. The communication method according to  claim 15 ,
   wherein the number of receiving time slots and the number of transmitting time slots are independent of each other.     
     
     
       17. The communication method according to  claim 15 ,
   wherein in said adjacent receiving and transmitting time slots said receiving time slot precedes said adjacent transmitting time slot.     
     
     
       18. The communication method according to  claim 17 ,
   wherein said guard period is provided at the end of said receiving time slot.     
     
     
       19. A communication unit for transmitting and receiving information in a time division duplex communication system, said information being transmitted in predetermined time frames having a predetermined number of time slots, comprising
   allocation means for allocating the time slots as receiving time slots and transmitting time slots dependent on an amount of information to be transferred, whereby each time frame comprises a receiving time slot and an adjacent transmitting time slot,        determining means for determining the amount of information to be transferred, whereby the allocation of time slots by the allocation means is changed when the amount of information to be transferred is changed, and        guard period means for providing a guard period in at least one of said receiving and adjacent transmitting time slots.     
     
     
       20. The communication unit according to  claim 19 ,
   wherein the number of receiving time slots and the number of transmitting time slots are independent of each other.     
     
     
       21. The communication unit according to  claim 20 ,
   wherein in said adjacent receiving and transmitting time slots, said receiving time slot precedes said adjacent transmitting time slot.     
     
     
       22. The communication unit according to  claim 21 ,
   wherein said guard period means provides said guard period at the end of said receiving time slot.     
     
     
       23. Communication method for transmitting and receiving information in a time division duplex communication system, comprising the steps of:
   allocating a predetermined number of time slots by which said time division duplex communication system transfers information, said predetermined number of time slots comprising fixed blocks of a receiving time slot and an adjacent transmitting time slot,        allocating at least the time slot adjacent to the receiving time slot of a fixed block as an additional receiving time slot and at least the time slot adjacent the transmitting time slot of said fixed block as an additional transmitting time slot dependent on an amount of information to be transferred, and        changing the allocation of said time slots when the amount of information to be transferred is changed.     
     
     
       24. The communication method according to  claim 23 ,
   wherein the number of additional receiving time slots and the number of additional transmitting time slots are independent of other.     
     
     
       25. The communication method according to  claim 23 ,
   wherein the receiving time slot and the transmitting time slot of the fixed block are allocated to a first communication unit, and the transmitting time slot precedes the receiving time slot.     
     
     
       26. The communication method according to  claim 25 ,
   wherein the additional time slots are allocated to said first communication unit.     
     
     
       27. The communication method according to  claim 25     wherein one time frame having time slots is assigned to several communication units and said additional time slots in said time frame are assigned to communication units different from said first communication unit.     
     
     
       28. The communication method according to  claim 23 ,
   wherein an additional time slot of a preceding fixed block and an additional time slot of a succeeding fixed block are adjacent each other, and a guard period is provided in at least one of said adjacent additional time slots.     
     
     
       29. The communication method according to  claim 28 ,
   wherein said additional time slot of said preceding fixed block is a receiving time slot and said additional time slot of said succeeding fixed block is a transmitting time slot, and said guard period is provided at the end of said receiving time slot.     
     
     
       30. A communication unit for transmitting and receiving information in a time division duplex communication system, said information being transmitted in a predetermined number of time slots, said predetermined number of time slots comprising a fixed block of one receiving time slot and one transmitting time slot adjacent to each other, said communication unit comprising:
   allocation means for allocating at least the time slot adjacent the receiving time slot of a fixed block as an additional receiving time slot and at least the time slot adjacent the transmitting    time slot of said fixed block as an additional transmitting time slot dependent on an amount of information to be transferred, and        determining means for determining the amount of information to be transferred, whereby the allocation of time slots by said allocation means is changed when the amount of information to be transferred is changed.     
     
     
       31. The communication unit according to  claim 30 ,
   wherein the number of additional receiving time slots and the number of additional transmitting time slots are independent of each other.     
     
     
       32. The communication unit according to  claim 30 ,
   further comprising guard period means for providing a guard period in at least one of adjacent additional time slots included in a preceding fixed block or a succeeding fixed block.     
     
     
       33. The communication unit according to  claim 32 ,
   wherein said guard period means provides said guard period at the end of an additional receiving time slot when said additional receiving time slot precedes an additional transmitting time slot.     
     
     
       34. A communication device for transmitting and/or receiving information in time frames having predetermined time slots in a time division duplex communication system, said communication device comprising:
   means for allocating the predetermined time slots into a number of receiving time slots and a number of transmitting time slots;        means for changing the allocation of said time slots based on an amount of information to be transferred; and        means for providing a guard period between a receiving time slot which is one of said allocated receiving time slots and a succeeding adjacent transmitting time slot which is one of said allocated transmitting time slots.     
     
     
       35. A communication method for transmitting and/or receiving information in time frames having predetermined time slots in a time division duplex communication system, comprising the steps of:
   allocating the predetermine time slots into a number of receiving time slots and a number of transmitting time slots;        changing the allocation of said time slots based on an amount of information to be transferred; and        providing a guard period between a receiving time slot which is one of said allocated receiving time slots and a succeeding adjacent transmitting time slot which is one of said allocated transmitting time slots.