Smooth transition between predictive and mobile-assisted spectral allocation
Technologies are generally described for providing a transition between predictive and mobile-assisted spectral allocation. In some examples, wireless devices may be enabled to determine adequacy of theft allocated spectral path to meet their communication needs by analyzing signal-to-noise ratios (SNRs) of their assigned sub-carriers. If a wireless device determines a current sub-carrier to be inadequate based on the analysis, it may send information associated with preferred sub-carriers to a base station. The base station may determine one or more nearby good clusters based on a comparison of a sequence of received preferred sub-carriers and the spectral paths represented by the nearby cluster centers, and select a re-allocated spectral path with shortest information distance to the sequence of preferred sub-carriers.
1. A method for spectral allocation in wireless networks, the method comprising:
receiving information pertaining to a preferred spectral path from a mobile device, the preferred spectral path comprising a subset of time-frequency vectors allocated to the mobile device with signal-to-noise ratios (SNRs) higher than a predefined threshold;
selecting a particular nearby cluster for the preferred spectral path, wherein the particular nearby cluster corresponds to spatial and temporal grid points near present space-time coordinates of the mobile device;
comparing the preferred spectral path to the particular nearby cluster to determine whether the particular nearby cluster has a time-frequency vector distance that is less than a particular threshold; and
in response to a determination that the particular nearby cluster has a time-frequency vector distance that is less than the particular threshold, forming a new spectral path by scheduling a next transmission for the mobile device at one or more time-frequency vectors in the particular nearby cluster and adding the new spectral path to a set of spectral paths associated with acceptable performance: else
scheduling the next transmission for the mobile device at the preferred spectral path received from the mobile device until another particular nearby cluster is determined to have a time-frequency vector distance that is less than the particular threshold when compared to the preferred spectral path.
2. The method according to claim 1 , wherein selecting the particular nearby cluster comprises:
computing, a respective information distance between the preferred spectral path and one or more nearby clusters; and
based on the respective information distance, identifying the particular nearby cluster.
3. The method according to claim 2 , wherein the particular nearby cluster is a good cluster that has a minimum vector distance from the preferred spectral path.
4. The method according to claim 1 , wherein the time-frequency vector distance is one of a Hamming distance and a Levenshtein distance.
5. The method according to claim 1 , wherein selecting, the particular nearby cluster comprises selecting the particular nearby duster among one or more nearby clusters with the time-frequency vector distance between a center of the nearby cluster and the preferred spectral path less than the particular threshold.
6. The method according to claim 5 , wherein the particular threshold is about 10%.
7. The method according to claim 5 , further comprising determining the particular threshold based on a coherence bandwidth of the mobile device.
8. A controller for a wireless network configured to transition between predictive allocation and mobile-assisted spectral allocation, the controller comprising:
a communication module configured to communicate with a plurality of mobile devices over a wireless network, wherein a mobile device from the plurality of mobile devices is configured to monitor an actual number of bits received as a transmission moves along a present spectral path, and compare the actual number of bits received to a scheduled number of bits;
a processor coupled to the communication module, the processor configured to:
receive information pertaining to a preferred spectral path from the mobile device in response to a determination by the mobile device that the actual number of bits received is less than the scheduled number of bits by a threshold, wherein the preferred spectral path for the mobile device comprises a subset of time-frequency vectors allocated to the mobile device with signal-to-noise ratios (SNRs) higher than a predefined threshold;
select a particular nearby cluster for the preferred spectral path, wherein the particular nearby cluster corresponds to spatial and temporal grid points near present space-time coordinates of the mobile device; and
in response to a determination that the particular nearby cluster has a time-frequency vector distance that is less than a particular threshold when compared to the preferred spectral path schedule a next transmission for the mobile device at one or more time-frequency vectors in the particular nearby cluster.
9. The controller according to claim 8 , wherein the processor is configured to receive the information pertaining, to the preferred spectral path by receiving sub-carrier specification information for one or more preferred sub-carriers from the mobile device.
10. The controller according to claim 8 , wherein the processor is further configured to use a string matching technique to determine if the preferred spectral path and the particular nearby cluster match the predefined criterion.
11. The controller according to claim 8 , wherein the processor is further configured to receive the preferred spectral path information from the mobile device in form of channel state information (CSI).
12. The controller according to claim 8 , wherein the processor is further configured to schedule the next transmission at the preferred spectral path if the predefined criterion is not matched.
13. The controller according to claim 8 , wherein the particular nearby duster is a duster that corresponds to spatial and/or temporal arid points surrounding present space and/or time coordinates of the mobile device.
14. The controller according to claim 8 , wherein the controller is part of a base station.
15. The controller according to claim 8 , wherein the wireless network is one of an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (eUTRAN), a long term evolution (LTE) network, an LTE-Advanced network, a high speed packet access (HSPA) network, or an advanced HSPA network.