Apparatus and method for OFDM data communications
View Patent ↗A radio system employing Orthogonal Frequency Division Multiplexed (OFDM) includes a Base Transceiver Station (BTS) along with a number of mobile terminals located within a coverage area of the BTS. In this system, a target mobile terminal is provided with a focused transmission beam to receive high data rate traffic information while the remainder of the mobile terminals are provide with pilot and signalling information. To achieve both objectives, a BTS is implemented with a transmission apparatus that generates a directional transmission beam for the data traffic information. In one design, this directional beam transmits the pilot and signalling information along with the data traffic information by rotating the beam within the coverage area. In another design, the BTS has a transmission apparatus that generates more than one transmission beam. In one case, the BTS transmits a directional transmission beam for the data traffic information required by the target mobile terminal and a second broad transmission beam for the pilot and signalling information required by the all of the mobile terminals. In another case, the BTS transmits two directional transmissions beams, one beam for data traffic information and one rotating beam for pilot and signalling information.
1. An Orthogonal Frequency Division Multiplexed (OFDM) Base Transceiver Station (BTS) arranged to communicate with a plurality of mobile terminals within a coverage area including at least one target mobile terminal, the BTS comprising:
a processing apparatus that operates to receive and process service and data traffic information; and
a transmission apparatus that operates to receive the processed service and data traffic information, to transmit the processed service information on a first set of carriers to the mobile terminals within the coverage area with at least one first transmission beam and to transmit the processed data traffic information on a second set of carriers to the target mobile terminal on at least one second transmission beam, the second transmission beam being a directional transmission beam.
2. An OFDM BTS according to claim 1 , wherein the service information comprises pilot information and signalling information.
3. An OFDM BTS according to claim 1 , wherein the data traffic information comprises data traffic pilot information.
4. An OFDM BTS according to claim 1 , wherein the first transmission beam is sufficiently broad for each of the mobile terminals within the coverage area to receive the processed service information.
5. An OFDM BTS according to claim 4 , wherein the transmission apparatus comprises at least one first transmission beam output path, the first transmission beam output path comprising a transmitter coupled to the processing apparatus and an antenna coupled to the transmitter; and
wherein the first transmission beam output path receives the processed service information from the processing apparatus and operates to generate the first transmission beam.
6. An OFDM BTS according to claim 5 , wherein the transmission apparatus comprises a plurality of first transmission beam output paths, each of the first transmission beam output paths comprising a transmitter coupled to the processing apparatus and a directional antenna coupled to its respective transmitter; and
wherein each of the first transmission beam output paths receives the processed service information from the processing apparatus and operates to generate a portion of the first transmission beam, each of the portions of the first transmission beam being focussed on a portion of the coverage area.
7. An OFDM BTS according to claim 5 , wherein the transmission apparatus further comprises a plurality of second transmission beam output paths, each of the second transmission beam output paths comprising a phase adjuster coupled to the processing apparatus and further coupled in series with a transmitter and an antenna; and
wherein the second transmission beam output paths each receive the processed data traffic information from the processing apparatus and operate together to generate the directional second transmission beam by selectively adjusting their respective phase adjusters.
8. An OFDM BTS according to claim 7 , wherein the first transmission beam output path and one of the second transmission beam output paths share a common transmitter and antenna; and
wherein the shared transmitter receives the processed service information from the processing apparatus and receives phase adjusted data traffic information from the output of the phase adjuster within the particular second transmission beam output path.
9. An OFDM BTS according to claim 5 , wherein the transmission apparatus further comprises a switch coupled to the processing apparatus and a plurality of second transmission beam output paths coupled to the switch, each of the second transmission beam output paths comprising a transmitter coupled to the switch and a directional antenna coupled to its corresponding transmitter; and
wherein the switch receives the processed data traffic information from the processing apparatus and selectively forwards the processed data traffic information to a set of the second transmission beam output paths to generate the directional second transmission beam.
10. An OFDM BTS according to claim 9 , wherein the set of the second transmission beam output paths to generate the directional second transmission beam comprises one second transmission beam output path.
11. An OFDM BTS according to claim 5 , wherein the transmission apparatus further comprises a second transmission beam transmitter coupled to the processing apparatus, a switch coupled to the second transmission beam transmitter and a plurality of second transmission beam directional antennas coupled to the switch; and
wherein the switch receives the processed data traffic information from the second transmission beam transmitter and selectively forwards the processed data traffic information to a set of the second transmission beam directional antennas to generate the directional second transmission beam.
12. An OFDM BTS according to claim 11 , wherein the set of the second transmission beam directional antennas to generate the directional second transmission beam comprises one second transmission beam directional antenna.
13. An OFDM BTS according to claim 1 , wherein the first transmission beam is a directional transmission beam; and
wherein the BTS is operable to modify the direction of focus of the directional first transmission beam in order for each of the mobile terminals within the coverage area to receive the processed service information.
14. An OFDM BTS according to claim 13 , wherein the BTS modifies the direction of focus of the directional first transmission beam such that each of the mobile terminals within the coverage area is focussed by the directional first transmission beam for a corresponding time period in a repetitive fashion.
15. An OFDM BTS according to claim 13 , wherein the transmission apparatus comprises a plurality of first transmission beam output paths, each of the first transmission beam output paths comprising a phase adjuster coupled to the processing apparatus and further coupled in series with a transmitter and an antenna; and
wherein the first transmission beam output paths each receive the processed service information from the processing apparatus and operate together to generate the directional first transmission beam by selectively adjusting their respective phase adjusters.
16. An OFDM BTS according to claim 15 , wherein the transmission apparatus further comprises a plurality of second transmission beam output paths, each of the second transmission beam output paths comprising a phase adjuster coupled to the processing apparatus and further coupled in series with a transmitter and an antenna; and
wherein the second transmission beam output paths each receive the processed data traffic information from the processing apparatus and operate together to generate the directional second transmission beam by selectively adjusting their respective phase adjusters.
17. An OFDM BTS according to claim 16 , wherein at least one of the first transmission beam output paths and at least one of the second transmission beam output paths share a common transmitter and antenna; and
wherein the shared transmitter operates to receive phase adjusted service information from the output of the phase adjuster within the at least one first transmission beam output path and to receive phase adjusted data traffic information from the output of the phase adjuster within the at least one second transmission beam output path.
18. An OFDM BTS according to claim 13 , wherein the transmission apparatus comprises a plurality of output paths, each output path comprising a first transmission beam phase adjuster coupled to the processing apparatus, a second transmission beam phase adjuster coupled to the processing apparatus, a transmitter coupled to both its respective first and second phase adjusters and an antenna coupled to its respective transmitter;
wherein the output paths each receive the processed service information from the processing apparatus at their respective first transmission beam phase adjusters and the output paths operate together to generate the directional first transmission beam by selectively adjusting their respective first transmission beam phase adjusters; and
wherein the output paths each receive the processed data traffic information from the processing apparatus at their respective second transmission beam phase adjusters and the output paths operate together to generate the directional second transmission beam by selectively adjusting their respective second transmission beam phase adjusters.
19. An QFDM BTS according to claim 13 , wherein the transmission apparatus comprises a first transmission beam switch coupled to the processing apparatus and a plurality of first transmission beam output paths coupled to the first transmission beam switch, each of the first transmission beam output paths comprising a transmitter coupled to the first transmission beam switch and a directional antenna coupled to its corresponding transmitter; and
wherein the first transmission beam switch receives the processed service information from the processing apparatus and selectively forwards the processed service information to a set of the first transmission beam output paths to generate the directional first transmission beam.
20. An OFDM BTS according to claim 19 , wherein the transmission apparatus further comprises a second transmission beam switch coupled to the processing apparatus and a plurality of second transmission beam output paths coupled to the second transmission beam switch, each of the second transmission beam output paths comprising a transmitter coupled to the second transmission beam switch and a directional antenna coupled to its corresponding transmitter; and
wherein the second transmission beam switch receives the processed data traffic information from the processing apparatus and selectively forwards the processed data traffic information to a set of the second transmission beam output paths to generate the directional second transmission beam.
21. An OFDM BTS according to claim 20 , wherein the set of the first transmission beam output paths in which the first transmission beam switch forwards the processed service information comprises one first transmission beam output path and the set of the second transmission beam output paths in which the second transmission beam switch forwards the processed data traffic information comprises one second transmission beam output path.
22. An OFDM BTS according to claim 20 , wherein at least one of the first transmission beam output paths and at least one of the second transmission beam output paths share a common transmitter and directional antenna; and
wherein the shared transmitter is operable to receive the processed service information from the first transmission beam switch and to receive the processed data traffic information from the second transmission beam switch.
23. An OFDM BTS according to claim 13 , wherein the transmission apparatus comprises a first transmission beam switch, a second transmission beam switch and a plurality of output paths, each output path comprising a transmitter coupled to both the first and second transmission beam switches and an antenna coupled to its respective transmitter; and
wherein the first transmission beam switch receives the processed service information from the processing apparatus and selectively forwards the processed service information to a set of the output paths to generate the directional first transmission beam and the second transmission beam switch receives the processed data traffic information from the processing apparatus and selectively forwards the processed data traffic information to a set of the output paths to generate the directional second transmission beam.
24. An OFDM BTS according to claim 1 further comprising at least one Peak-Average-Power Ratio (PAPR) block coupled between the processing apparatus and the transmission apparatus, the PAPR block operating to reduce peak power of the processed service and data traffic information.
25. An OFDM BTS according to claim 1 , wherein the processing apparatus comprises at least one data traffic and service information processor that operates to receive and process data traffic and service information and an inverse fast fourier transform block coupled between the data traffic and service information processor and the transmission apparatus.
26. An OFDM BTS according to claim 25 , wherein the at least one data traffic and service information processor comprises a data traffic information processor, a signalling information processor and a pilot information processor; and
wherein each of the data traffic, signalling and pilot information processors perform at least one of modulation mapping, interleaving, rate matching, forward error correction encoding on the data traffic, signalling and pilot information respectively.
27. An OFDM BTS according to claim 1 , wherein the transmission apparatus operates to transmit the processed service information with a plurality of transmission beams.
28. An OFDM BTS according to claim 27 , wherein the transmission apparatus operates to transmit the processed service information with at least one signalling information transmission beam and at least one pilot information transmission beam.
29. An OFDM BTS according to claim 1 , wherein the transmission apparatus operates to transmit the processed data traffic information with a plurality of transmission beams.
30. An OFDM BTS according to claim 29 , wherein the transmission apparatus operates to transmit the processed data traffic information with at least one audio traffic information transmission beam and at least one non-audio traffic information transmission beam.
31. An OFDM BTS according to claim 29 , wherein the transmission apparatus operates to transmit the processed data traffic information with at least one audio traffic information transmission beam and at least one video traffic information transmission beam.
32. An Orthogonal Frequency Division Multiplexed (OFDM) Base Transceiver Station (BTS) arranged to communicate with a plurality of mobile terminals within a coverage area, the BTS comprising:
a processing apparatus that operates to receive and process service and data traffic information; and
a transmission apparatus that operates to receive the processed service and data traffic information, to transmit the processed service information on a first set of carriers and the processed data traffic information on a second set of carriers using a directional transmission beam;
wherein the BTS is operable to modify the direction of focus of the directional transmission beam in order for each of the mobile terminals within the coverage area to receive the processed service information.
33. An OFDM BTS according to claim 32 , wherein the service information comprises pilot information and signalling information.
34. An OFDM BTS according to claim 32 , wherein the BTS modifies the direction of focus of the directional transmission beam such that each of the mobile terminals within the coverage area is focussed by the directional beam for a corresponding time period in a repetitive fashion.
35. An OFDM BTS according to claim 32 , wherein the transmission apparatus comprises a plurality of output paths, each of the output paths comprising a phase adjuster coupled to the processing apparatus and further coupled in series with a transmitter and an antenna; and
wherein the output paths each receive the processed service and data traffic information from the processing apparatus and operate together to generate the directional transmission beam by selectively adjusting their respective phase adjusters.
36. An OFDM BTS according to claim 32 , wherein the transmission apparatus comprises a switch coupled to the processing apparatus and a plurality of output paths coupled to the switch, each of the output paths comprising a transmitter coupled to the switch and a directional antenna coupled to its corresponding transmitter; and
wherein the switch receives the processed service and data traffic information from the processing apparatus and selectively forwards the information to a set of the output paths to generate the directional transmission beam.
37. An OFDM BTS according to claim 36 , wherein the set of the output paths in which the switch forwards the information comprises one output path.
38. An OFDM BTS according to claim 32 , wherein the transmission apparatus comprises a transmitter coupled to the processing apparatus, a switch coupled to the transmitter and a plurality of directional antennas coupled to the switch; and
wherein the switch receives the processed service and data traffic information from the transmitter and selectively forwards the information to a set of the directional antennas to generate the directional transmission beam.
39. An OFDM BTS according to claim 38 , wherein the set of the directional antennas in which the switch forwards the information comprises one directional antenna.
40. An OFDM BTS according to claim 32 further comprising at least one Peak-Average-Power Ratio (PAPR) block coupled between the processing apparatus and the transmission apparatus, the PAPR block operating to reduce peak power of the processed service and data traffic information.
41. An OFDM BTS according to claim 32 , wherein the processing apparatus comprises at least one data traffic and service information processor that operates to receive and process data traffic and service information and an inverse fast fourier transform block coupled between the data traffic and service information processor and the transmission apparatus.
42. An OFDM BTS according to claim 41 , wherein the at least one data traffic and service information processor comprises a data traffic information processor, a signalling information processor and a pilot information processor; and
wherein each of the data traffic, signalling and pilot information processors perform at least one of modulation mapping, interleaving, rate matching, forward error correction encoding on the data traffic, signalling and pilot information respectively.
43. A radio system comprising an Orthogonal Frequency Division Multiplexed (OFDM) Base Transceiver Station (BTS) and a plurality of mobile terminals within a coverage area of the BTS, at least one of the mobile terminals being a target mobile terminal;
wherein the OFDM BTS is operable to receive service and data traffic information, to transmit the service information on a first set of carriers to the mobile terminals within the coverage area with a first transmission beam and to transmit the data traffic information on a second set of carriers to the target mobile terminal with a second transmission beam, the second transmission beam being a directional transmission beam.