Communicating RF terminal capability
Apparatus and method for communicating control data indicative of the capability of RF receiver equipment in wireless telecommunications devices. The control data is then used to allocate transmission resources to the telecommunications devices (including MTC-type terminals). Where a virtual carrier is established to carry data for a given MTC-type device, the position of the center frequency for that virtual carrier is assigned on the basis of both the capability of the RF receiver equipment of that terminal and the degree of traffic congestion on the frequency band at which the virtual carrier has been established.
1. A machine type communication (MTC) terminal, comprising:
processing circuitry configured to
determine a bandwidth status of the MTC terminal, said bandwidth status defining a mode of virtual channel operation to which the MTC terminal is to be assigned by a base station based on whether a receiving architecture of the MTC terminal has a narrower baseband bandwidth than a RF bandwidth;
transmit MTC control data to the base station, the MTC control data including the bandwidth status; and
receive radio-frequency (RF) signals from the base station in the mode of virtual channel operation assigned by the base station according to the bandwidth status, the processing circuitry of the MTC terminal further configured to
receive signals via a first virtual channel at a different frequency than a center frequency of a host carrier when the bandwidth status indicates the baseband bandwidth of the MTC terminal is narrower than the RF bandwidth, and
when the bandwidth status indicates the baseband bandwidth of the MTC is not narrower, receive signals via the first virtual channel at
(a) the center frequency of the host carrier when an available capacity at the center frequency is above a given amount, and
(b) another different frequency than the center frequency of the host carrier when the available capacity at the center frequency is not above the given amount, wherein
the MTC terminal and the base station communicate data in a wireless telecommunications system using a first plurality of Orthogonal Frequency Division Multiplex (OFDM) sub-carriers that span a first frequency bandwidth,
the mode of virtual channel operation relates to a first virtual channel of a group of sub-carriers selected from said first plurality of OFDM sub-carriers,
the first virtual channel is different from a second virtual channel of the group of sub-carriers, and
another MTC terminal receives RF signals from the base station in a second mode of virtual channel operation that relates to the second virtual channel.
2. The MTC terminal as claimed in claim 1 , wherein the bandwidth status includes information identifying an RF receiving architecture of the processing circuitry selected from a group including intermediate frequency conversion, direct conversion, normal narrowband and baseband narrowband.
3. The MTC terminal as claimed in claim 1 , wherein the bandwidth status corresponds to at least one parameter indicating a bandwidth size capability of the MTC terminal.
4. The MTC terminal as claimed in claim 1 , wherein
at least one of said first plurality of OFDM sub-carriers is an unused center frequency of the first frequency bandwidth, and
the first virtual channel spans a second frequency bandwidth that is narrower than the first frequency bandwidth.
5. The MTC terminal as claimed in claim 4 , wherein the MTC terminal has a first bandwidth status representing an indication that the MTC terminal is capable of receiving the RF signals over the first frequency bandwidth and receiving baseband signals over the second frequency bandwidth.
6. The MTC terminal as claimed in claim 4 , wherein the MTC terminal has a second bandwidth status representing an indication that the MTC terminal is capable of both receiving RF signals and baseband signals over the second frequency bandwidth.
7. The MTC terminal as claimed in claim 1 , wherein the bandwidth status represents an indication of an RF receiving architecture of the processing circuitry selected from a group including intermediate frequency conversion, direct conversion, normal narrowband and baseband narrowband.
8. A method for communicating control data between a machine type communication (MTC) terminal and a base station, the method comprising:
determining a bandwidth status of the MTC terminal, said bandwidth status defining a mode of virtual channel operation to which the MTC terminal is to be assigned by the base station based on whether a receiving architecture of the MTC terminal has a narrower baseband bandwidth than a RF bandwidth;
transmitting MTC control data to the base station, the MTC control data including the bandwidth status; and
receiving, by the MTC terminal, radio-frequency (RF) signals from the base station in the mode of virtual channel operation assigned by the base station according to the bandwidth status, said receiving including
receiving at a different frequency than a center frequency of a host carrier when the bandwidth status indicates the baseband bandwidth of the MTC terminal is narrower than the RF bandwidth, and
when the bandwidth status indicates the baseband bandwidth of the MTC is not narrower, receiving signals via the first virtual channel at
(a) the center frequency of the host carrier when an available capacity at the center frequency is above a given amount, and
(b) another different frequency than the center frequency of the host carrier when the available capacity at the center frequency is not above the given amount, wherein
the MTC terminal and the base station communicate data in a wireless telecommunications system using a first plurality of Orthogonal Frequency Division Multiplex (OFDM) sub-carriers that span a first frequency bandwidth,
the mode of virtual channel operation relates to a first virtual channel of a group of sub-carriers selected from said first plurality of OFDM sub-carriers,
the first virtual channel is different from a second virtual channel of the group of sub-carriers, and
another MTC terminal receives RF signals from the base station in a second mode of virtual channel operation that relates to the second virtual channel.
9. The method as claimed in claim 8 , wherein
at least one of said first plurality of OFDM sub-carriers is an unused center frequency of the first frequency bandwidth, and
the first virtual channel spans a second frequency bandwidth that is narrower than the first frequency bandwidth.