Mixed-mode MIMO detector in a local area network
View Patent ↗A wireless device with multiple antennae and configured to support orthogonal frequency-division multiplexed (OFDM), multiple-input multiple-output (MIMO) communications of a wireless local area network (LAN) among multiple wireless devices over a shared wireless communication medium on a shared communication channel. The wireless access device comprises: a mixed-mode MIMO detector configured to allocate a mix of linear and non-linear MIMO detectors among received OFDM sub-channels of the shared communication channel, thereby reducing a level of complexity associated with reception of MIMO streams exclusively via non-linear MIMO detectors.
1. A wireless device configured to support multiple-input multiple-output (MIMO) communications on a plurality of orthogonal frequency-division multiplexed (OFDM) sub-Channels of a shared communication channel on a wireless local area network (WLAN); and the wireless device comprising:
a sub-channel correlation monitor to monitor receive path correlations of each of the OFDM sub-channels on the shared communication channel and to determine at least the correlation level for each sub-channel relative to other sub-channels;
a pool of linear and non-linear MIMO detectors each switchably selectable for performing MIMO detection on a designated one of the OFDM sub-channels; and
a sub-channel allocator coupled to the sub-channel correlation monitor and to the pool of MIMO detectors and responsive to the relative correlation levels determined by the sub-channel correlation monitor to switchably couple uncorrelated ones of the sub-channels to linear ones among the pool of detectors and to switchably couple correlated ones of the sub-channels to non-linear ones among the pool of MIMO detectors whereby the allocation of the linear and non-linear detectors among received OFDM sub-channels varies with MIMO detection requirements of each sub-channel.
2. The wireless device of claim 1 , further comprising:
a resource monitor to monitor processing resources available on the wireless device; and
the sub-channel allocator further responsive to changes in processing resources as determined by the resource monitor to re-allocate linear and non-linear detectors, thereby balancing sub-channel MIMO detection requirements and available processing resources.
3. A method of operating a wireless device configured to support multiple-input multiple-output (MIMO) communications on a plurality of orthogonal frequency-division multiplexed (OFDM) sub-channels of a shared communication channel on a wireless local area network (WLAN); and the method comprising:
determining at least the sub-channel receive path correlation level for each OFDM sub-channel relative to other sub-channels;
providing a pool of linear MIMO detectors and non-linear MIMO detectors; and
allocating uncorrelated ones of the sub-channels to linear ones among the pool of MIMO detectors and correlated ones of the sub-channels to non-linear ones among the pool of MIMO detectors provided in the providing act responsive to the sub-channel receive path correlations determined in the determining act; whereby the allocation of the linear and non-linear detectors among received OFDM sub-channels varies with MIMO detection requirements of each sub-channel.
4. The method for operating a wireless device of claim 3 wherein the allocating act further comprises:
determining an associated processing complexity for each of the linear and non-linear detectors provided in the providing act; and
allocating the linear and non-linear MIMO detectors to received OFDM sub-channels based both on the relative sub-channel receive path correlations of each OFDM sub-channel as determined in the first determining act together with an associated processing complexity associated with each MIMO detector type as determined in the second determining act, thereby balancing MIMO detection requirements and available processing resources.
5. The method for operating a wireless device of claim 3 wherein the determining act further comprises:
identifying a prominent column of a corresponding sub-channel matrix for each of the OFDM sub-channels; and
ordering the OFDM sub-channels based on a magnitude of each associated prominent column identified in the identifying act.
6. A method of operating a wireless device with multiple antennae and configured to support orthogonal frequency-division multiplexed (OFDM), multiple-input multiple-output (MIMO) communications of a wireless local area network (LAN) among multiple wireless devices over a shared wireless communication medium on a shared communication channel; and the method comprising;
providing both linear together with non-linear MIMO detectors; and
allocating a mix of the linear and non-linear MIMO detectors provided in the providing act, among received OFDM sub-channels of the shared communication channel, thereby reducing a level of complexity associated with reception of MIMO streams exclusively via non-linear MIMO detectors, and further:
determining at least relative sub-channel receive path correlations among the OFDM sub-channels by:
converting a sub-channel matrix “H n ” for each sub-channel “n” to a correlaton matrix “R” where R=H n H *H n where “H n H ” comprises an Hermetian Matrix.
7. A means for operating a wireless device with multiple antennae and configured to support orthogonal frequency-division multiplexed (OFDM), multiple-input multiple-output (MIMO) communications of a wireless local area network (LAN) among multiple wireless devices over a shared wireless communication medium on a shared communication channel; and the means comprising:
means for providing both linear together with non-linear MIMO detectors; and
means for allocating a mix of the linear and non-linear MEMO detectors provided in the providing act, among received OFDM sub-channels of the shared communication channel, thereby reducing a level of complexity associated with reception of MIMO streams exclusively via non-linear MIMO detectors; and wherein the means for allocating further comprises:
means for determining at least relative sub-channel receive path correlations among the OFDM sub-channels by: converting a sub-channel matrix “H n ” for each sub-channel “n” to a correlation matrix “R” where R=H n H *H n where “H n H ” comprises an Hermetian Matrix.
8. The wireless device of claim 1 , further comprising:
a switch fabric coupled to the pool of MIMO detectors and responsive to the sub-channel allocator to switchably couple uncorrelated ones of the sub-channels to linear ones among the pool of detectors and to switchably couple correlated ones of the sub-channels to non-linear ones among the pool of MIMO detectors.
9. The method of claim 3 , wherein the allocating act, further comprises:
varying the allocation of linear and non-linear MIMO detectors as a modulation protocol of the communication channel and associated constellation size increases in complexity; whereby the allocation of the linear and non-linear detectors among received OFDM sub-channels varies with both the MIMO detection requirements of each sub-channel together with the modulation protocol of the communication channel.