Methods and systems for selecting a TTI bundle size
A radio access network (RAN) determines whether transmission time interval (TTI) bundling is warranted for a wireless communication device (WCD) based on at least a power headroom report from the WCD. In response to determining that TTI bundling is warranted, the RAN selects a TTI bundle size, N, for the WCD and instructs the WCD to use the selected TTI bundle size. The TTI bundle size, N, could be selected from among a set of predefined values, such as N=2, N=3, and N=4. The selection could be based on various factors, such as a utilization of an uplink shared channel, a re-transmission rate of the WCD, and/or a remaining battery life of the WCD.
1. A method, comprising:
a radio access network (RAN) receiving a power headroom report from a wireless communication device (WCD);
the RAN determining that transmission time interval (TTI) bundling is warranted for the WCD based on at least the power headroom report;
in response to determining that TTI bundling is warranted for the WCD, the RAN selecting a TTI bundle size, N, for the WCD from among at least three values based on at least a utilization of an uplink shared channel, the at least three values including N=2, N=3, and N=4, wherein the RAN selecting the TTI bundle size, N, for the WCD based on at least a utilization of an uplink shared channel comprises:
if the utilization of the uplink shared channel is in a low range, selecting the TTI bundle size of N=4;
if the utilization of the uplink shared channel is in a medium range, selecting the TTI bundle size of N=3; and
if the utilization of the uplink shared channel is in a high range, selecting the TTI bundle size of N=2; and
the RAN instructing the WCD to use the selected TTI bundle size.
2. The method of claim 1 , wherein TTI bundling is supported for only one or more service classes, and wherein the RAN determining that TTI bundling is warranted for the WCD is further based on the RAN determining that the WCD is buffering for transmission data associated with a service class for which TTI bundling is supported.
3. The method of claim 1 , further comprising the RAN determining the utilization of the uplink shared channel based on an extent to which uplink resource blocks associated with a given time period have been allocated.
4. A method, comprising:
a radio access network (RAN) receiving a power headroom report from a wireless communication device (WCD);
the RAN determining that transmission time interval (TTI) bundling is warranted for the WCD based on at least the power headroom report;
in response to determining that TTI bundling is warranted for the WCD, the RAN selecting a TTI bundle size, N, for the WCD from among at least three values based on at least a re-transmission rate of the WCD, the at least three values including N=2, N=3, and N=4, wherein the RAN selecting the TTI bundle size, N, for the WCD based on at least a re-transmission rate of the WCD comprises:
if the re-transmission rate of the WCD is in a high range, selecting the TTI bundle size of N=4;
if the re-transmission rate of the WCD is in a medium range, selecting the TTI bundle size of N=3; and
if the re-transmission rate of the WCD is in a low range, selecting the TTI bundle size of N=2; and
the RAN instructing the WCD to use the selected TTI bundle size.
5. The method of claim 4 , further comprising the RAN determining the re-transmission rate of the WCD based on an extent to which transmissions by the WCD during a given time period have been re-transmissions.
6. The method of claim 4 , wherein TTI bundling is supported for only one or more service classes, and wherein the RAN determining that TTI bundling is warranted for the WCD is further based on the RAN determining that the WCD is buffering for transmission data associated with a service class for which TTI bundling is supported.
7. A method, comprising:
a radio access network (RAN) receiving a power headroom report from a wireless communication device (WCD);
the RAN receiving an indication of a remaining battery life of the WCD;
the RAN determining that transmission time interval (TTI) bundling is warranted for the WCD based on at least the power headroom report;
in response to determining that TTI bundling is warranted for the WCD, the RAN selecting a TTI bundle size, N, for the WCD from among at least three values based on at least the remaining battery life of the WCD, the at least three values including N=2, N=3, and N=4, wherein the RAN selecting the TTI bundle size, N, for the WCD based on at least the remaining battery life of the WCD comprises:
if the remaining battery life of the WCD is in a high range, selecting the TTI bundle size of N=4;
if the remaining battery life of the WCD is in a medium range, selecting the TTI bundle size of N=3; and
if the remaining battery life of the WCD is in a low range, selecting the TTI bundle size of N=2; and
the RAN instructing the WCD to use the selected TTI bundle size.
8. The method of claim 7 , wherein the RAN receiving an indication of a remaining battery life of the WCD comprises the RAN receiving a battery life report from the WCD.
9. The method of claim 7 , wherein TTI bundling is supported for only one or more service classes, and wherein the RAN determining that TTI bundling is warranted for the WCD is further based on the RAN determining that the WCD is buffering for transmission data associated with a service class for which TTI bundling is supported.