BANDWIDTH ASYMMETRIC COMMUNICATION SYSTEM BASED ON OFDM AND TDMA
First Claim
1. Communication system, comprising:
- a plurality of terminals each having an uplink transmission unit (1) for transmitting radio frequency OFDM signals at a radio frequency,an access point having an uplink receiving unit (4) for concurrently receiving said radio frequency OFDM signals from at least two terminals, said OFDM signals being Orthogonal Frequency Division Multiplex (OFDM) modulated, wherein the bandwidth of said uplink transmission units and of the transmitted radio frequency OFDM signals is smaller than the bandwidth of said uplink receiving unit, wherein the bandwidth of at least two uplink transmission units and of their transmitted radio frequency OFDM signals is different, and wherein the uplink transmission unit is adapted to assign different connections for concurrently transmitting radio frequency OFDM signals to different sub-carriers in the same time slots or to the same or different sub-carriers in different time slots, the plurality of terminals and the access point being adapted for using a superframe structure for communicating input data and control data, a superframe comprising a downlink period (DL period) comprising downlink preambles, a number of broadcast channels (BCH-i), a number of downlink time slots for data and pilot tones, and an uplink period (UL period) comprising a number of uplink time slots for data and pilot tones, each uplink time slot being preceded by a downlink synchronization sequence for frequency/clock, phase, and timing adjustment for the following time slot and a transmission-reception turnaround interval for switching the terminal from receiver mode to transmitter mode and the access point from transmitter mode to receiver mode.
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Abstract
The present invention relates to a communication system comprising a plurality of terminals each having an uplink transmission unit (1) for transmitting radio frequency OFDM signals at a radio frequency and an access point having an uplink receiving unit (4) for concurrently receiving said radio frequency OFDM signals from at least two terminals, said OFDM signals being Orthogonal Frequency Division Multiplex (OFDM) modulated, wherein the bandwidth of said uplink transmission units and of the transmitted radio frequency OFDM signals is smaller than the bandwidth of said uplink receiving unit, that the bandwidth of at least two uplink transmission units and of their transmitted radio frequency OFDM signals is different and that the uplink transmission unit is adapted to assign different connections for concurrently transmitting radio frequency OFDM signals to different sub-carriers in the same time slots or to the same or different sub-carriers in different time slots.
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Citations
18 Claims
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1. Communication system, comprising:
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a plurality of terminals each having an uplink transmission unit (1) for transmitting radio frequency OFDM signals at a radio frequency, an access point having an uplink receiving unit (4) for concurrently receiving said radio frequency OFDM signals from at least two terminals, said OFDM signals being Orthogonal Frequency Division Multiplex (OFDM) modulated, wherein the bandwidth of said uplink transmission units and of the transmitted radio frequency OFDM signals is smaller than the bandwidth of said uplink receiving unit, wherein the bandwidth of at least two uplink transmission units and of their transmitted radio frequency OFDM signals is different, and wherein the uplink transmission unit is adapted to assign different connections for concurrently transmitting radio frequency OFDM signals to different sub-carriers in the same time slots or to the same or different sub-carriers in different time slots, the plurality of terminals and the access point being adapted for using a superframe structure for communicating input data and control data, a superframe comprising a downlink period (DL period) comprising downlink preambles, a number of broadcast channels (BCH-i), a number of downlink time slots for data and pilot tones, and an uplink period (UL period) comprising a number of uplink time slots for data and pilot tones, each uplink time slot being preceded by a downlink synchronization sequence for frequency/clock, phase, and timing adjustment for the following time slot and a transmission-reception turnaround interval for switching the terminal from receiver mode to transmitter mode and the access point from transmitter mode to receiver mode. - View Dependent Claims (2, 3, 4, 7)
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5. (canceled)
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6. (canceled)
- 8. Method for communicating in a communication system comprising a plurality of terminals each having an uplink transmission unit (1) for transmitting radio frequency OFDM signals at a radio frequency and an access point having an uplink receiving unit (4) for concurrently receiving said radio frequency OFDM signals from at least two terminals, said OFDM signals being Orthogonal Frequency Division Multiplex (OFDM) modulated, wherein the bandwidth of said uplink transmission unit and of the transmitted radio frequency OFDM signals is smaller than the bandwidth of said uplink receiving unit, wherein the bandwidth of at least two uplink transmission units and of their transmitted radio frequency OFDM signals is different, and wherein different connections for concurrently transmitting radio frequency OFDM signals are assigned to different sub-carriers in the same time slots or to the same or different sub-carriers in different time slots, the plurality of terminals and the access point being adapted for using a superframe structure for communicating input data and control data, a superframe comprising a downlink period (DL period) comprising downlink preambles, a number of broadcast channels (BCH-i), a number of downlink time slots for data and pilot tones, and an uplink period (UL period) comprising a number of uplink time slots for data and pilot tones, each uplink time slot being preceded by a downlink synchronization sequence for frequency/clock, phase, and timing adjustment for the following time slot and a transmission-reception turnaround interval for switching the terminal from receiver mode to transmitter mode and the access point from transmitter mode to receiver mode.
- 10. Terminal for use in a communication system comprising an uplink transmission unit (1) for transmitting radio frequency OFDM signals at a radio frequency for reception by an access point having an uplink receiving unit (4) for concurrently receiving said radio frequency OFDM signals from at least two terminals, said OFDM signals being Orthogonal Frequency Division Multiplex (OFDM) modulated, wherein the bandwidth of said uplink transmission unit and of the transmitted radio frequency OFDM signals is smaller than the bandwidth of said uplink receiving unit, and wherein the uplink transmission unit is adapted to assign different connections for concurrently transmitting radio frequency OFDM signals to different sub-carriers in the same time slots or to the same or different sub-carriers in different time slots, the terminal being adapted for using a superframe structure for communicating input data and control data, a superframe comprising a downlink period (DL period) comprising downlink preambles, a number of broadcast channels (BCH-i), a number of downlink time slots for data and pilot tones, and an uplink period (UL period) comprising a number of uplink time slots for data and pilot tones, each uplink time slot being preceded by a downlink synchronization sequence for frequency/clock, phase, and timing adjustment for the following time slot and a transmission-reception turnaround interval for switching the terminal from receiver mode to transmitter mode and the access point from transmitter mode to receiver mode.
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18-31. -31. (canceled)
Specification