Data transmission method and a radio system

• US 6,625,138 B2
• Filed: 10/09/2001
• Issued: 09/23/2003
• Est. Priority Date: 02/12/1998
• Status: Expired due to Fees

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Kalliojärvi, Kari, Soininen, Pekka, Hottinen, Ari, Toskala, Antti, Wichman, Risto, Kärnä, Juha
• Primary Examiner(s): Rao, Seema S.
• Assistant Examiner(s): Harper, Kevin C.
• Application Number:
  US09/974,325
• Publication Number:
  US 20020114297A1
• Time in Patent Office: 714 Days
• Field of Search: 370/310, 370/315, 370/319-320, 370/335, 370/342, 370/441, 370/443, 370/464, 370/479, 370/328-329, 375/130, 375/134-135, 375/137, 375/142, 375/144, 375/145, 375/148-150, 455/522, 455/69-70
• US Class Current: 370/342
• CPC Class Codes: H04B 1/7097 Interference-related aspects
• CPC Class Codes: H04W 74/008 with additional processing of random access related information at receiving side
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

The invention relates to a data transmission method used in a CDMA-type radio system. A base station and terminal equipments exchange data at least in a packet switched mode, and a terminal equipment transmits to the base station on a random access channel a random access signal comprising at least a preamble (100) and a data part (102) multiplied by a spreading code. A predetermined set of spreading codes and signature sequences (104) are stored in the terminal equipment, and each signature sequence (104) determines one spreading code. The terminal equipment selects one signature sequence (104) by a random process from the set of signature sequences and adds the selected signature sequence (104) to the preamble (100) of the random access signal. Further, the terminal equipment uses the spreading code corresponding to the selected signature sequence (104) in the data part (102) of the random access signal. Interference cancellation is performed at the base station according to the signature sequence (104) of the preamble (100) of the received random access signal, such that at least the interference caused by the received data part (102) is eliminated from at least one other received signal in order to improve detection.

Claims

1. A data transmission method used in a CDMA-type radio system comprising at least one base station and a plurality of terminal equipments that exchange data at least in a packet switched mode, wherein

transmitting by a terminal equipment a random access signal to the base station on a random access channel,

transmitting by a base station data about interference cancellation capacity of the base station to the terminal equipment, and the terminal equipment determines the transmission power of the random access signal it transmits using at least partially the signalled data on the interference cancellation capacity of the base station.

2. A method according to claim 1, wherein

performing interference cancellation at the base station using the structure of the received random access signal, such that at least the interference caused by the random access signal is at least partly cancelled from at least one other received signal.

3. A radio system that is of the CDMA type and that comprises at least one base station and a plurality of terminal equipments which are arranged to exchange data at least in a packet switched mode, a terminal equipment being arranged to transmit to the base station a random access signal on a random access channel, wherein

the base station is arranged to transmit data about its interference cancellation capacity to the terminal equipment, and the terminal equipment is arranged to determine the transmission power of the random access signal it transmits using at least partially the signalled data on the interference cancellation capacity of the base station.

4. A radio system according to claim 3, wherein the base station is arranged to perform interference cancellation using the structure of the received random access signal, such that the base station is arranged to cancel at least partly the interference caused by the random access signal from at least one other received signal in order to increase transmission capacity and to improve detection.

5. A radio system according to claim 4, wherein the terminal equipment comprises signature sequence means and spreading code means that are arranged to provide a predetermined set of spreading codes and signature sequences, each signature sequence determining one spreading code;

wherein

the terminal equipment is arranged to select one signature sequence by a random process from the set of signature sequences, and to add the selected signature sequence to the preamble of the random access signal;

the terminal equipment is arranged to use the spreading code corresponding to the selected signature sequence in the data part of the random access signal.