| 摘要 |
A method of communicating data to mobile terminals from an OFDM wireless communications network which provides a wireless access interface for communicating the data using a plurality of OFDM sub-carriers comprises providing a first control channel having a bandwidth corresponding to a first frequency band at a first temporal position within a sub-frame, and transmitting resource allocation messages in the first control channel allocating communications resources of a first group of OFDM sub-carriers to communications terminals of a first type and allocating communications resources of a second group of OFDM sub-carriers to communications terminals of a second type. The second group of the plurality of OFDM sub-carriers is smaller than the first group of the plurality of OFDM sub-carriers and the second frequency band is selected from within the first frequency band to form a virtual carrier. The method includes providing a second control channel within the second frequency band within the second group of OFDM sub-carriers in a second temporal position within a sub-frame, and transmitting control information which is specific to the terminals of the second type operating to receive the data via the second group of OFDM sub- carriers. The communications terminals of the second type there by receive resource allocation messages from the first control channel to allocate resources within the second frequency band forming the virtual carrier and receive control information,which is specific to the communications terminals of the second type,which are receiving data from the second frequency band of the virtual carrier via a second control channel. Accordingly, there is provided a logical separation of full bandwidth LTE type terminals and communications terminals of a reduced bandwidth of the second type in respect of the transmission of control information, but uses the same resource allocation messages for both the full-bandwidth LTE terminals and the reduced bandwidth terminals of the second type thereby improving compatibility with conventional LTE networks. |
