Link adaptation for LTE uplink

A method for performing link adaptation, comprising:

• performing at a base station in a wireless network,
• classifying transmissions from user equipment into a first group of time-critical traffic and a second group of non-time-critical traffic;
• determining a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• and
• determining a second MCS for the transmissions in the second group;
• signaling to a user equipment the selected MCS in the group associated with the traffic type to be received from the user equipment;
• receiving a signal transmitted by the user equipment based on the signaled MCS;
• collecting throughput measurements for a user equipment in the second group over a predefined number of scheduled transmission time intervals;
• averaging the throughput measurements to compute a relative throughput variation across a measurement interval;
• comparing the relative throughput variation to a hysteresis threshold;
• modifying a next backoff parameter value relative to a current backoff parameter value if the relative throughput variation is greater than the hysteresis threshold;
• and
• setting the next backoff parameter value equal to the current backoff parameter value if the relative throughput variation is not greater than the hysteresis threshold.

A base station, comprising:

• a controller configured to:
• classify transmissions from user equipment into a first group of time-critical traffic and a second group of non-time-critical traffic;
• determine a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• measure a success rate from P initial transmissions by a user equipment in the first group;
• estimate a block error rate based upon the success rate of a defined number of initial transmissions;
• increase a current backoff parameter if the estimated block error rate is greater than a target block error rate to create a new backoff parameter;
• decrease the current backoff parameter if the estimated block error rate is less than the target block error rate to create the new backoff parameter;
• determine a second MCS for the transmissions in the second group;
• and
• a modem configured to signal the selected MCS to the user equipment and receive the transmissions from the user equipment.

A base station, comprising:

• a controller configured to:
• classify transmissions from user equipment into a first group of time-critical traffic and a second group of non-time-critical traffic;
• determine a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• determine a second MCS for the transmissions in the second group;
• collect throughput measurements for a user equipment in the second group over a predefined number of scheduled transmission time intervals;
• average the throughput measurements across a measurement interval;
• compute a relative throughput variation across the measurement interval;
• compare the relative throughput variation to a hysteresis threshold;
• modify a next backoff parameter value relative to a current backoff parameter value if the relative throughput variation is greater than the hysteresis threshold;
• set the next backoff parameter value equal to the current backoff parameter value if the relative throughput variation is not greater than the hysteresis threshold;
• and
• a modem configured to signal the selected MCS to the user equipment and receive the transmissions from the user equipment.

A method for performing link adaptation, comprising:

• classifying received transmissions into a first group of time-critical traffic and a second group of non-time-critical traffic;
• measuring a success rate from P initial received transmissions in the first group;
• estimating a block error rate based upon the success rate of a defined number of received initial transmissions;
• using said block error rate estimation to determine a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• collecting data rate measurements, in number of successfully transmitted bits per second, different from said success rate measurement, for received transmissions in the second group over a predefined number of scheduled transmission time intervals;
• averaging the data rate measurements across a measurement interval;
• using said averaged data rate measurements to determine a second MCS for the transmissions in the second group;
• transmitting the selected MCS in the group associated with the traffic type to be received in the received transmissions;
• and
• anticipating receipt of a responsive transmission based on the signaled MCS.

A base station, comprising:

• circuitry for classifying received transmissions into a first group of time-critical traffic and a second group of non-time-critical traffic;
• circuitry for measuring a success rate from P initial received transmissions in the first group;
• circuitry for estimating a block error rate based upon the success rate of a defined number of received initial transmissions;
• circuitry for using said block error rate estimation to determine a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• circuitry for collecting data rate measurements, in number of successfully transmitted bits per second, different from said success rate measurement, for received transmissions in the second group over a predefined number of scheduled transmission time intervals;
• circuitry for averaging the data rate measurements across a measurement interval;
• circuitry for using said averaged data rate measurements to determine a second MCS for the transmissions in the second group;
• circuitry for transmitting the selected MCS in the group associated with the traffic type to be received in the received transmissions;
• and
• circuitry for receiving a responsive transmission based on the signaled MCS.

A base station, comprising:

• a controller configured to:
• classify received transmissions into a first group of time-critical traffic and a second group of non-time-critical traffic;
• measure a success rate from P initial received transmissions in the first group;
• estimate a block error rate based upon the success rate of a defined number of received initial transmissions;
• use said block error rate estimation to determine a first Modulation and Coding Scheme (MCS) for the transmissions in the first group;
• collect data rate measurements, in number of successfully transmitted bits per second, different from said success rate measurement, for received transmissions in the second group over a predefined number of scheduled transmission time intervals;
• average the data rate measurements across a measurement interval;
• use said averaged data rate measurements to determine a second MCS for the transmissions in the second group;
• and
• a modem enabled to transmit the selected MCS from the base station and to receive in the base station a transmission responsive to the selected MCS.