Method and device for determining a number of MIMO layers
The embodiments herein relate to a method in a base station for communicating with a user equipment in the communication network. The base station is configured to communicate with the user equipment according to a selectable of at least two user equipment categories. Based on information about a selected user equipment category, the base station determines a first number of maximum transmission layers supported by the base station. The base station communicates with the user equipment according to up to the determined first number of maximum transmission layers and according to the selected user equipment category.
1. A method in a base station for communicating with a user equipment in a communication network, the base station being configured to communicate with the user equipment according to a selectable of at least two user equipment categories including a user equipment category associated with release 8/9 of Long Term Evolution (LTE) and a user equipment category associated with release 10 of LTE, the method comprising:
based on information about a selected LTE user equipment category selected from the at least two user equipment categories including a user equipment category associated with release 8/9 of LTE and a user equipment category associated with release 10 of LTE, determining a first number of maximum, Multiple Input Multiple Output (MIMO) transmission layers supported by the base station; and
communicating with the user equipment according to up to the determined first number of maximum, MIMO transmission layers and according to the selected user equipment category.
2. The method according to claim 1 , further comprising transmitting information to the user equipment about the first number of maximum, MIMO transmission layers.
3. The method according to claim 1 , further comprising:
receiving, from the user equipment, information about the at least two user equipment categories and a number of maximum, MIMO transmission layers for each user equipment category.
4. The method according to claim 3 , wherein the information about the first number of maximum, MIMO transmission layers is transmitted to the user equipment when the first number of maximum, MIMO transmission layers is larger than a second number of maximum, MIMO transmission layers.
5. The method according to claim 4 , further comprising:
receiving channel state information according to the first number of maximum, MIMO transmission layers from the user equipment, the channel state information comprising information about a state of a radio channel between the user equipment and the base station.
6. The method according to claim 1 , wherein the information about the first number of maximum, MIMO transmission layers is transmitted to the user equipment via a radio resource control, referred to as RRC, protocol.
7. The method according to claim 1 , wherein the communicating with the user equipment according to up to the first number of maximum, MIMO transmission layers and according to the selected user equipment category is a downlink communication in a direction from the base station to the user equipment.
8. The method according to claim 1 ,
wherein the selected user equipment category and the first number of maximum, MIMO transmission layers are associated with release 8/9 of LTE, and a second number of maximum, MIMO transmission layers are associated with release 10 of LTE, or
wherein the selected user equipment category and the first number of maximum, MIMO transmission layers are associated with release 10 of LTE and the second number of maximum, MIMO transmission layers are associated with release 8/9 of LTE.
9. A base station for communicating with a user equipment in a communication network, the base station being configured to communicate with the user equipment according to a selectable of at least two user equipment categories including a user equipment category associated with release 8/9 of Long Term Evolution (LTE) and a user equipment category associated with release 10 of LTE, the base station comprising:
a determining unit configured to, based on information about a selected user equipment category selected from the at least two user equipment categories including a user equipment category associated with release 8/9 of LTE and a user equipment category associated with release 10 of LTE, determine a first number of maximum, Multiple Input Multiple Output (MIMO) transmission layers supported by the base station; and
a communicating unit configured to communicate with the user equipment according to up to the first number of maximum, MIMO transmission layers and according to the selected user equipment category.
10. The base station according to claim 9 , further comprising:
a transmitting port configured to transmit information to the user equipment about the first number of maximum, MIMO transmission layers.
11. The base station according to claim 9 , further comprising:
a receiving port configured to receive, from the user equipment, information about the at least two user equipment categories and a number of maximum, MIMO transmission layers for each user equipment category.
12. The base station according to claim 1 , wherein the information about the first number of maximum, MIMO transmission layers is transmitted to the user equipment when the first number of maximum, MIMO transmission layers is larger than a second number of maximum, MIMO transmission layers.
13. The base station according to claim 9 , wherein the receiving port is further configured to receive channel state information according to the first number of maximum, MIMO transmission layers from the user equipment, the channel state information comprising information about a state of a radio channel between the user equipment and the base station.
14. The base station according to claim 9 , wherein the transmitting port is further configured to transmit the information about the first number of maximum, MIMO transmission layers to the user equipment via a radio resource control, referred to as RRC, protocol.
15. The base station according to claim 9 , wherein the communication with the user equipment according to up to the first number of maximum, MIMO transmission layers and according to the selected user equipment category is a downlink communication in a direction from the base station to the user equipment.
16. The base station according to claim 9 ,
wherein the selected user equipment category and the first number of maximum, MIMO transmission layers are associated with release 8/9 of long term evolution, referred to as LTE, and a second number of maximum, MIMO transmission layers are associated with release 10 of LTE, or
wherein the selected user equipment category and the first number of maximum, MIMO transmission layers are associated with release 10 of LTE and the second number of maximum, MIMO transmission layers are associated with release 8/9 of LTE.