Multi-carrier power pooling
Novel techniques for pooling the available transmit power of a beam across the subcarriers that are or that are scheduled to be in use (and not across all available subcarriers) are disclosed. The scheduled subcarriers may be located in the same or different carriers of a modulation transmitter modulation system, and the pooled transmit power may be allocated or distributed across the scheduled subcarriers of the beam. Modulation symbols or resource elements may be transmitted in accordance with allocated, per-subcarrier power budgets, thereby maximizing the SNIR of signals that are transmitted in the beam via the scheduled subcarriers. Additionally, the allocation of the pooled transmit power to various subcarriers may continuously and/or dynamically vary over time, e.g., based on traffic demands, interference characteristics, etc., as well as based on subsequent scheduling of subcarriers to transmit subsequent modulation symbols or resource elements.
1. A wireless communication system, comprising:
a modulation transmitter configured to wirelessly communicate with a plurality of user terminals via a plurality of non-overlapping beams formed in a frequency band, each non-overlapping beam of the plurality of non-overlapping beams subject to a per-beam power limit; and
a controller configured to control resource elements transmitted by the modulation transmitter by varying a respective power budget of each of the resource elements that are scheduled to be in use across a plurality of carriers utilized by the modulation transmitter to wirelessly communicate with the plurality of user terminals,
each carrier supporting a plurality of subcarriers,
each resource element corresponding to a respective, single subcarrier over a duration of a respective, single modulation symbol, and
the varying of the respective power budget of the each of the resource elements scheduled to be in use to wirelessly communicate with the plurality of user terminals based on at least one of:
(a) a variation in a particular bandwidth of a particular beam of the plurality of non-overlapping beams, the particular beam allocated to communicate with a particular user terminal, and the particular beam having a bandwidth that is less than a total bandwidth of the frequency band; or
(b) a variation in a total number of resource elements that are scheduled to be in use across the plurality of carriers utilized by the modulation transmitter to wirelessly communicate with the plurality of user terminals, the total number of scheduled resource elements being less than a total number of available resource elements across the plurality of carriers.
2. The wireless communication system of claim 1 , wherein the variation of the respective power budget of each of the resource elements is based on the variation in the total number of scheduled resource elements and a variation of a per-beam power budget allocated among the total number of scheduled resource elements, the per-beam power budget corresponding to the per-beam power limit.
3. The wireless communication system of claim 2 , wherein each scheduled resource element is allocated an average power budget per scheduled resource element, the average power budget per scheduled resource element based on the per-beam power budget.
4. The wireless communication system of claim 1 , wherein the variation of the respective power budget of each of the resource elements is based on the variation in the particular bandwidth of the particular beam, and the particular beam is subject to a per-beam power budget corresponding to the per-beam power limit.
5. The wireless communication system of claim 4 , wherein a second bandwidth of a second non-overlapping beam included in the plurality of the non-overlapping beams is different than the particular bandwidth of the particular beam.
6. The wireless communication system of claim 1 , wherein the particular bandwidth of the particular beam is allocated across multiple carriers supported by the particular beam.
7. The wireless communication system of claim 6 , wherein the controller is further configured to:
control a modulation scheme of data to be transmitted via the modulation transmitter to the particular user terminal based on a channel characteristic corresponding to the particular user terminal, thereby generating a group of modulation symbols; and
allocate at least two modulation symbols included in the group of modulation symbols across the multiple carriers supported by the particular beam for transmission to the particular user terminal.
8. The wireless communication system of claim 7 , wherein the modulation scheme is an OFDM modulation scheme, and the group of modulation symbols corresponds to one or more OFDM symbols.
9. The wireless communication system of claim 1 , wherein at least one of:
the frequency band is an unlicensed frequency band; or
the modulation transmitter is configured to wirelessly communicate with the plurality of user terminals in accordance with LTE.
10. The wireless communication system of claim 1 , wherein the varying of the respective power budget of each of the resource elements is based on both the variation in the particular bandwidth of the particular beam and the variation in the total number of scheduled resource elements.
11. A method of maximizing the signal-to-interference-plus-noise ratio (SINR) of wireless signals transmitted to a particular user terminal, the method comprising:
controlling, by a controller of a wireless communication system, resource elements transmitted by a modulation transmitter, the modulation transmitter configured to wirelessly communicate with a plurality of user terminals via a plurality of non-overlapping beams formed in a frequency band, each non-overlapping beam of the plurality of non-overlapping beams subject to a per-beam power limit, and the controlling of the resource elements including varying a respective power budget of each of the resource elements that are scheduled to be in use across a plurality of carriers utilized by the modulation transmitter to wirelessly communicate with the plurality of user terminals,
each carrier supporting a plurality of subcarriers,
each resource element corresponding to a respective, single subcarrier over a duration of a respective, single modulation symbol, and
the varying of the respective power budget of the each of the resource elements scheduled to be in use to wirelessly communicate with the plurality of user terminals based on at least one of:
(a) a variation in a particular bandwidth of a particular beam of the plurality of non-overlapping beams, the particular beam allocated to communicate with a particular user terminal, and the particular beam having a bandwidth that is less than a total bandwidth of the frequency band; or
(b) a variation in a total number of resource elements that are scheduled to be in use across the plurality of carriers utilized by the modulation transmitter to wirelessly communicate with the plurality of user terminals, the total number of scheduled resource elements being less than a total number of available resource elements across the plurality of carriers.
12. The method of claim 11 ,
further comprising allocating a per-beam power budget among the total number of scheduled resource elements, the per-beam power budget corresponding to the per-beam power limit; and
wherein varying of the respective power budget of each of the resource elements is based on the variation in the total number of scheduled resource elements and a variation of the per-beam power budget allocated among the total number of scheduled resource elements.
13. The method of claim 12 , wherein allocating the per-beam power budget among the total number of scheduled resource elements includes allocating an average power budget per scheduled resource element, the average power budget per scheduled resource element based on the per-beam power budget.
14. The method of claim 11 , wherein varying of the respective power budget of each of the resource elements is based on the variation in the particular bandwidth of the particular beam, and the particular beam is subject to a per-beam power budget corresponding to the per-beam power limit.
15. The method of claim 14 , wherein a second bandwidth of a second non-overlapping beam included in the plurality of the non-overlapping beams is different than the particular bandwidth of the particular beam, and the second non-overlapping beam is subject to a respective per-beam power budget corresponding to the per-beam power limit.
16. The method of claim 11 , further comprising allocating the particular bandwidth of the particular beam across multiple carriers supported by the particular beam.
17. The method of claim 16 , further comprising:
controlling, by the controller, a modulation scheme of data to be transmitted via the modulation transmitter to the particular user terminal based on a channel characteristic corresponding to the particular user terminal, thereby generating a group of modulation symbols; and
allocating at least two modulation symbols included in the group of modulation symbols across the multiple carriers for transmission to the particular user terminal.
18. The method of claim 17 , wherein the modulation scheme is an OFDM modulation scheme.
19. The method of claim 11 , wherein at least one of:
the frequency band is an unlicensed frequency band; or
the modulation transmitter is configured to wirelessly communicate with the plurality of user terminals in accordance with LTE.
20. The method of claim 11 , wherein varying of the respective power budget of each of the resource elements is based on the variation in the particular bandwidth of the particular beam and based on the variation in the total number of scheduled resource elements.