To provide techniques for implementing a multiple-access hybrid OFDM-CDMA system that may be used to provide wireless voice and/or data communications.
In one aspect of a multiple-access OFDM-CDMA system, data spreading is performed in a frequency domain by spreading each data stream with a respective spreading code selected from a set of available spreading codes. To support multiple access, system resources may be allocated and de-allocated to users (e.g., spreading codes may be assigned to users as needed, and transmit power may be allocated to users). Variable rate data for each user may be supported via a combination of spreading adjustment and transmit power scaling. Interference control techniques are also provided to improve system performance via power control of downlink and/or uplink transmissions to achieve the desired level of performance while minimizing interference. A pilot may be transmitted by each transmitter unit to assist the receiver units perform acquisition, timing synchronization, carrier recovery, handoff, channel estimation, coherent data demodulation, and so on.
KETCHUM JOHN W
HOWARD STEVEN J
WALLACE MARK
| JPH0738496A | 1995-02-07 |
| EP1128592A2 | 2001-08-29 |
Kurata Masatoshi
Satoshi Kono
Makoto Nakamura
Yoshihiro Fukuhara
Takashi Mine
Toshio Shirane
Sadao Muramatsu
Nobuhisa Nogawa
Kocho Chojiro
Naoki Kono
Katsu Sunagawa
Tetsuya Kazama
Katsumura Hiro
Shoji Kawai
Tatsushi Sato
Takashi Okada
Mihoko Horiuchi
Takenori Masanori
Takuzo Ichihara
Yamashita Gen