Reference symbol distribution method and apparatus
At least some reference symbols dedicated to a particular communication device are transmitted in resource blocks allocated to other devices. This way, reference symbol assignments are not unduly restricted by other constraints placed on the boundary elements of a resource block. According to an embodiment, data and reference signals are transmitted by transmitting a resource block allocated to a first communication device. The resource block includes a plurality of resource elements, each resource element corresponding to a modulation symbol. At least one reference symbol associated with the resource block and dedicated to the first communication device is transmitted in a resource block allocated to a second communication device. On the receive side, the communication device can perform channel estimation based on reference symbols dedicated to the device that are transmitted in resource blocks allocated to the device and in resource block(s) allocated to other communication device(s).
1. A method of transmitting data and reference signals, comprising:
transmitting a resource block allocated to a first communication device, the resource block including a plurality of resource elements, each resource element corresponding to a modulation symbol;
transmitting at least one reference symbol associated with the resource block and dedicated to the first communication device in a resource block allocated to a second communication device;
further comprising transmitting a plurality of OFDM reference symbols dedicated to the first communication device in a plurality of resource blocks allocated to other communication devices so that the OFDM reference symbols encompass the resource block allocated to the first communication device in the time-frequency domain; and
transmitting OFDM data symbols dedicated to the first communication device outside the resource block allocated to the first communication device, but within the region of the time-frequency domain encompassed by the OFDM reference symbols.
2. A communication device, comprising:
a baseband processor configured to allocate a resource block to a first communication device and dedicate a plurality of reference symbols associated with the resource block to the first communication device, the resource block including a plurality of resource elements, each resource element corresponding to a modulation symbol;
a transmitter configured to transmit the resource block to the first communication device and transmit at least one of the reference symbols dedicated to the first communication device in a resource block allocated to a second communication device, wherein the reference symbols dedicated to the first communication device are OFDM reference symbols and the transmitter is configured to transmit at least some of the OFDM reference symbols in resource blocks allocated to other communication devices so that the OFDM reference symbols encompass the resource block allocated to the first communication device in the time-frequency domain and further wherein the transmitter is configured to transmit a plurality of OFDM data symbols dedicated to the first communication device outside the resource block allocated to the first communication device, but within the region of the time-frequency domain encompassed by the OFDM reference symbols.
3. A method of estimating channel conditions, comprising:
processing data transmitted to a first communication device in a resource block allocated to the first communication device, the resource block having a plurality of resource elements, each resource element corresponding to a modulation symbol;
estimating channel conditions by the first communication device based on a plurality of reference symbols associated with the resource block and dedicated to the first communication device, wherein at least one of the reference symbols is received in a resource block allocated to a second communication device, and further wherein the reference symbols are OFDM reference symbols and at least some of the OFDM reference symbols are received in a plurality of resource blocks allocated to other communication devices, the OFDM reference symbols encompassing the resource block allocated to the first communication device in the time-frequency domain and further wherein processing OFDM data symbols dedicated to the first communication device and received outside the resource block allocated to the first communication device, but within the region of the time-frequency domain encompassed by the OFDM reference symbols.
4. A communication device, comprising a baseband processor configured to:
process data transmitted to the communication device in a resource block allocated to the communication device, the resource block having a plurality of resource elements, each resource element corresponding to a modulation symbol;
estimate channel conditions based on a plurality of reference symbols associated with the resource block and dedicated to the communication device, wherein at least one of the reference symbols is received in a resource block allocated to a different communication device, wherein the reference symbols are OFDM reference symbols, at least some of the OFDM reference symbols are received in a plurality of resource blocks allocated to other communication devices and encompass the resource block allocated to the communication device in the time-frequency domain and the baseband processor is configured to estimate the channel conditions based on the OFDM reference symbols and further wherein the baseband processor is configured to process OFDM data symbols dedicated to the communication device and received outside the resource block allocated to the communication device, but within the region of the time-frequency domain encompassed by the OFDM reference symbols.