Resolving channel state information outdating
It is described a method of operating a base station and a base station which uses a communication channel depending on channel state related information and time information e.g. a prediction time. In this way, problems due to outdating of the channel state related information may be overcome and a feedback overhead may be reduced. According to other embodiments, other parameters like a used prediction method, a prediction horizon, etc. are used to provide a better scenario adaption. Other embodiments relate to combined long term prediction and short term prediction and respective timing settings. Other embodiments relate to a method of operating a user equipment and a user equipment which is adapted for communicating the required time information between the base station and the user equipment.
1. A method comprising:
receiving, at a base station, channel state related information from a user equipment of a communication network, the channel state related information being based on a measurement performed by the user equipment, the channel state related information being a prediction time provided by the user equipment on the basis of the measurement;
using a communication channel between the base station and the user equipment depending on the received channel state related information and a time information which is associated with a measurement time at which the measurement has been performed, the time information comprising a prediction horizon indicating the accuracy of the channel state related information at a specified time after the measurement; and
receiving from the user equipment a message specifying a current mean prediction horizon of the user equipment and organizing the regular channel state information reporting based on the received message.
2. The method of claim 1 , wherein:
said time information indicates a predetermined time interval; and
the communication channel is used at a later point of time different from said measurement time only if the later point of time is within said predetermined time interval from the measurement time.
3. The method of claim 1 , wherein taking into account the channel state related information comprises predicting a channel state information value for a point of time by taking into account the channel state related information.
4. The method of claim wherein
receiving channel state related information comprises receiving a long term prediction of channel state information and, subsequently, receiving a short term prediction of channel state information;
wherein said long term prediction is valid from a first point of time for a first time interval and said short term prediction is valid from a second point of time for a second time interval; and
wherein said first time interval extends from the first point of time beyond the second point of time.
5. The method of claim 1 , wherein:
the time information is at least partly fixedly defined.
6. The method of claim 1 , further comprising:
receiving from the user equipment operating parameters of the user equipment; and
at least partly setting the time information depending on operating parameters of the user equipment.
7. A method comprising:
receiving time information from a base station of a communication network, the time information comprising a prediction horizon indicating the accuracy of the channel state related information at a specified time after the measurement;
determining, depending on said time information, channel state related information on the basis of a measurement of the user equipment, the channel state information being a prediction time provided by the user equipment on the basis of the measurement; and
transmitting said channel state related information to the base station, wherein transmitting said determined channel state information comprises transmitting a message relating to a current mean state prediction horizon of the user equipment to the base station.
8. An apparatus comprising:
at least one processor;
memory storing a program of instructions;
wherein the memory storing the program of instructions is configured to, with the at least one processor, cause the apparatus to at least:
receive, at a base station, channel state related information from a user equipment of the communication network, the channel state related information being based on a measurement performed by the user equipment, the channel state related information being a prediction time provided by the user equipment on the basis of the measurement;
use a communication channel between the base station and the user equipment depending on the received channel state related information and a time information which is associated with a measurement time at which the measurement has been performed, the time information comprising a prediction horizon indicating the accuracy of the channel state related information at a specified time after the measurement; and
receive from the user equipment a message relating to a current mean prediction horizon of the user equipment and, based on the received message organize the regular channel state information reporting.
9. An apparatus according to claim 8 , wherein the apparatus is a base station and further comprising:
an interface for exchanging said channel state related information, or a quantity derived therefrom, with at least one similarly configured base station.
10. The apparatus of claim 8 , wherein:
said time information indicates a predetermined time interval; and
the communication channel is used at a later point of time different from said measurement time only if the later point of time is within said predetermined time interval from the measurement time.
11. The apparatus of claim 8 , wherein
taking into account the channel state related information comprises predicting a channel state information value for a point of time by taking into account the channel state related information.
12. An apparatus comprising:
at least one processor;
memory storing a program of instructions;
wherein the memory storing the program of instructions is configured to, with the at least one processor, cause the apparatus to at least:
receive time information from a base station of the communication network, the time information comprising a prediction horizon indicating the accuracy of the channel state related information at a specified time after the measurement;
determine, depending on said time information, channel state related information on the basis of a measurement taken by the user equipment, the channel state related information being a prediction time provided by the user equipment on the basis of the measurement; and
transmit said channel state related information to the base station, wherein transmitting said channel state related information comprises transmitting a message relating to a current mean prediction horizon of the user equipment to the base station.