Adaptive precoding in a MIMO wireless communication system
This invention presents methods for estimating MU-MIMO channel information using SU-MIMO channel information to choose a modulation and channel coding appropriate for the quality of the MU-MIMO channels, for adaptively selecting MU-MIMO precoding methods based on estimations of a plural of UEs and for compensating hardware impairments in MU-MIMO precoding.
1. A method for compensating hardware impairments and circuit conditions in precoding comprising
storing Hardware Impairment Parameters (HIPs) of a User Equipment (UE) that describe imperfections and/or nonlinearities in the UE hardware in a database that a Base Station (BS) can access to, wherein the UE has a Unique Device Identity (UDID) and said UE HIPs are associated with the UDID;
the BS acquiring the UDID of the UE;
the BS obtaining the stored HIPs of the UE from the database using the UDID; and
the BS using the obtained HIPs in the precoding to compensate hardware impairments and circuit conditions in the UE.
2. The method in claim 1 further comprising the BS obtaining HIPS of multiple UEs and using the obtained HIPs in a MU-MIMO precoding to compensate hardware impairments and circuit conditions in said multiple UEs.
3. The method in claim 1 , wherein the Hardware Impairment Parameters (HIPs) corresponding to different operating temperatures are stored in the database, further comprising
the BS requesting the UE to send the UE's real-time operating temperature to the BS,
the BS obtaining the HIPs corresponding to the received UE's operating temperature, and
the BS using HIPs corresponding to the received UE's operating temperature in the precoding compensation.
4. The method in claim 1 further comprising
the BS requesting a UE to feed back the UE's HIPs to the BS if the BS cannot obtain the HIPs of the UE using the UE's UDID; and
after receiving this request, the UE sending the UE's HIPs to the BS.
5. The method in claim 4 further comprising the BS sending the UE's HIPs to said database for storage.
6. The method in claim 1 further comprising when a handover is needed as the UE moves from a first BS to a second BS, the first BS sending the HIPs of said UE to the second BS through a network.
7. The method in claim 1 further comprising sharing said database in a network of multiple carriers.