Patent ID: 11936501
Assignee: NORDIC SEMICONDUCTOR ASA
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A radio receiver for receiving an OFDM data signal from a radio transmission system that transmits OFDM data signals over respective channels of a plurality of predetermined radio channels, each channel having a respective channel bandwidth and comprising a respective plurality of OFDM subcarriers, and that transmits predetermined reference signals at predetermined times on a reference-signal set of the respective plurality of OFDM subcarriers,
wherein the radio receiver comprises a local oscillator and a channel filter,
wherein the radio receiver is configured to tune a channel of the plurality of predetermined radio channels by:
controlling the local oscillator to generate a periodic signal;
receiving radio signals from the radio transmission system and mixing the radio signals with the periodic signal to generate a mixed signal; and
passing the mixed signal through the channel filter, wherein the channel filter has a passband that corresponds to the channel bandwidth of the tuned channel,

wherein the radio receiver is configured to receive, from the radio transmission system, allocation information identifying a set of allocated subcarriers, of the plurality of OFDM subcarriers in the tuned channel, on which to receive an OFDM data signal,
wherein the radio receiver is configured to use the allocation information to receive the OFDM data signal, from the radio transmission system, modulated on the set of allocated subcarriers, wherein, when the set of allocated subcarriers spans an allocated frequency range that is less than the channel bandwidth of the tuned channel and that is offset from a center of the tuned channel in an offset direction, the radio receiver is configured to offset the channel filter from the center of the tuned channel in said offset direction by a filter offset amount, such that the channel filter passes i) said OFDM data signal; ii) an in-allocation reference signal of the predetermined reference signals, received on a subcarrier of the set of allocated subcarriers; and iii) an out-of-channel reference signal of the predetermined reference signals, received on an out-of-channel subcarrier of the plurality of OFDM subcarriers that is located outside the tuned channel, and wherein the radio receiver comprises channel estimation logic configured to use both i) the in-allocation reference signal, and ii) the out-of-channel reference signal, to calculate a channel estimate for a subcarrier of the set of allocated subcarriers within the tuned channel.