Nortel Networks Corporation

Rockstar Bidco, LP

Apple Inc.

Christian Dubuc

Daniel Boudreau

William R Kirkland

Peiying Zhu

Wen Tong

Ming Jia

Jason Robert Duggan

Colin Brown

A transmitter () generates a first set of data symbols and a first pilot symbol () at a first time, and a second set of data symbols and a second pilot symbol () at a different, second time. The first () and second () pilot symbols are each represented by first () and second () pilot carriers, respectively, located at first () and second () predetermined sample frequencies, respectively, in a channel bandwidth. For the first pilot symbol (), the first () and second () pilot carriers have first and second predetermined values, respectively. For the second pilot symbol (), the first () and second () pilot carriers have third and fourth predetermined values, respectively. A receiver () measures the first, second, fourth and third predetermined values responsive to receiving the first () and second () pilot symbols to determine first, second, third and fourth estimates of channel distortion, respectively, for compensating and recovering the first and the second sets of data symbols.

System and method for I/Q imbalance compensation

A transmitter () generates a first set of data symbols and a first pilot symbol () at a first time, and a second set of data symbols and a second pilot symbol () at a different, second time. The first () and second () pilot. symbols are each represented by first () and second () pilot carriers, respectively, located at first () and second () predetermined sample frequencies, respectively, in a channel bandwidth. For the first pilot symbol (), the first () and second () pilot carriers have first and second predetermined values, respectively. For the second pilot symbol (), the first () and second () pilot carriers have third and fourth predetermined values, respectively. A receiver () measures the first, second, fourth and third predetermined values responsive to receiving the first () and second () pilot symbols to determine first, second, third and fourth estimates of channel distortion, respectively, for compensating and recovering the first and the second sets of data symbols.

The present invention divides the available sub-carriers in an OFDM symbol window into N groups of sub-carriers wherein each group will be associated with sub-bands. In one embodiment, the sub-carriers in a group are spread throughout the range of sub-carriers to improve frequency diversity, and the sub-carriers assigned to any one group are separated by a constant offset. The sub-carriers in the group may be offset by an integer power of two. Within each group, sub-bands are defined using frequency hopping patterns among sub-carriers in the group from one OFDM symbol window to another. A pseudo-random pattern may be employed for sub-carrier mapping from one OFDM symbol window to the next to effectively distribute the sub-bands across the selected band of sub-carriers for the group.

Sub-carrier allocation for OFDM

The present invention provides an improved channel quality indicator indicia for OFDM communication environments. In addition to taking into consideration carrier-to-interference ratios, the present invention also takes into consideration the degree to which the channel response varies among the sub-carriers throughout the OFDM frequency band. The carrier-to-interference ratio and the degree of channel response variation are directly or indirectly used by a base station to select coding and modulation schemes for transmissions from the base station to the mobile terminal reporting these factors. Further, scheduling of data sent to the mobile terminal and other mobile terminals competing for the same channel resources may also be based in part on the carrier-to-interference ratio and the degree to which the channel response varies.

Channel quality indicator for OFDM

A rotation by a phase offset is applied to symbols to be transmitted by one antenna relative to symbols to be transmitted from another antenna in a wireless communication system employing multi-element antennas at the transmitter. Such a phase offset allows the functionality of a MIMO system to be maintained when a MIMO channel degenerates. Advantageously, a MIMO system using the new signal design may provide a level of performance in a rich-scattering environment that is equivalent to a MIMO system using a known signal design. Furthermore, a MIMO system employing embodiments of the present invention may show significantly improvements in robustness over conventional MIMO systems.

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Aylmer, Canada

Christian Dubuc