Uplink resource allocation to control intercell interference in a wireless communication system
Embodiments of the present invention exploit the reciprocity of radio channels in TDD, and longer-term correlation between average uplink and downlink path losses in FDD wireless communication systems to enable distributed schedulers in an enhanced uplink system to allocate uplink transmission resources while preemptively managing intercell interference levels. Each cell's base station transmits a downlink reference signal at a known transmission power level. A mobile station monitors the received signal strength of the downlink reference signals from multiple base stations. The transmitted and received signal strength levels can be used by the mobile station to estimate the amount of intercell interference that the mobile station's uplink transmissions cause, and the mobile station's uplink transmission parameters are adjusted accordingly. In further embodiments, the received reference signal power levels, or values derived therefrom, are transmitted by the mobile station to its serving base station, where a scheduling algorithm uses the information to adjust one or more transmission parameters relating to a grant of uplink transmission resources to the UE, thereby controlling the intercell interference generated by the mobile station's uplink transmissions.
1. A method for allocating uplink transmission resources in a time division duplex based wireless communication system, the method comprising:
receiving, by a mobile station, reference signals transmitted by a serving station and at least one of neighboring base stations;
measuring, by the mobile station, received signal power levels for the respective reference signals;
determining, by the mobile station, a radio propagation condition between the mobile station and the serving base station and radio propagation conditions between the mobile station and the at least one of neighboring base stations and calculating, by the mobile station, a corresponding metric;
transmitting, by the mobile station, the metric to the serving base station; and
receiving, by the mobile station, an allocation of uplink transmission resources in response to the metric, wherein
the metric includes a ratio of the radio propagation condition between the mobile station and the serving base station and at least one of the radio propagation conditions between the mobile station and the neighboring base stations,
the uplink transmission resources include at least one of data rate, uplink transmission power, degree or nature of forward error correction, modulation format, and code resource usage, and
the radio propagation conditions are path gains or path losses, and the metric comprises a ratio of a path gain or path loss of the serving base station and path gains or path losses of the respective neighboring base stations.
2. The method of claim 1 , wherein the wireless communication system is described by a Third Generation partnership project Universal Mobile Telecommunication Standard, the base station is a Node-B, and the mobile station is a user equipment (UE).
3. The method of to claim 1 , wherein the metric comprises a ratio of a path gain of the serving base station and a path gain of a strongest of the neighboring base stations.
4. The method of claim 1 , wherein the uplink transmission resources are proportional to the metric.
5. The mobile station of claim 1 , wherein
the uplink transmission resources consist of the data rate, the uplink transmission power, the degree or nature of forward error correction, the modulation format, and the code resource usage.
6. A mobile station for a time division duplex based wireless communication system, comprising:
means for receiving reference signals transmitted by a serving base station and a at least one of neighboring base stations;
means for measuring received signal power levels for the respective reference signals;
means for determining a radio propagation condition between the mobile station and the serving base station and radio propagation conditions between the mobile station and the at least one of neighboring base stations and means for calculating a corresponding metric;
means for transmitting the metric to the serving base station; and
means for receiving an allocation of uplink transmission resources in response to the metric, wherein
the metric includes a ratio of the radio propagation condition between the mobile station and the serving base station and at least one of the radio propagation conditions between the mobile station and the neighboring base stations,
the uplink transmission resources include at least one of data rate, uplink transmission power, degree or nature of forward error correction, modulation format, and code resource usage, and
the radio propagation conditions are path gains or path losses, and the metric comprises a ratio of a path gain or path loss of the serving base station and path gains or path losses of the respective neighboring base stations.
7. The mobile station of claim 6 , wherein the wireless communication system is described by a Third Generation partnership project Universal Mobile Telecommunication Standard, the base station is a Node-B, and the mobile station is a user equipment (UE).
8. The mobile station of claim 6 , wherein the metric comprises a ratio of a path gain of the serving base station and a path gain of a strongest of the neighboring base stations.
9. The mobile station of claim 6 , wherein the uplink transmission resources are proportional to the metric.
10. A mobile station for a time division duplex based wireless communication system, comprising:
a receiver configured to receive reference signals transmitted by a serving base station and at least one of neighboring base stations;
a processing unit configured to measure received signal power levels for the respective reference signals, determine a radio propagation condition between the mobile station and the serving base station and radio propagation conditions between the mobile station and the at least one of neighboring base stations, and calculate a corresponding metric; and
a transmitter configured to transmit the metric to the serving base station, wherein
the receiver is further configured to receive an allocation of uplink transmission resources in response to the metric, and
the metric includes a ratio of the radio propagation condition between the mobile station and the serving base station and at least one of the radio propagation conditions between the mobile station and the neighboring base stations,
the uplink transmission resources include at least one of data rate, uplink transmission power, degree or nature of forward error correction, modulation format, and code resource usage, and
the radio propagation conditions are path gains or path losses, and the metric comprises a ratio of a path gain or path loss of the serving base station and path gains or path losses of the respective neighboring base stations.
11. The mobile station of claim 10 , wherein the metric comprises a ratio of a path gain of the serving base station and a path gain of a strongest of the neighboring base stations.
12. The mobile station of claim 10 , wherein the uplink transmission resources are proportional to the metric.
13. The mobile station of claim 10 , wherein the wireless communication system is described by a Third Generation partnership project Universal Mobile Telecommunication Standard, the base station is a Node-B, and the mobile station is a user equipment (UE).