Discrete soft handoff in CDMA wireless networks
OwnerPrathima Agrawal, David Famolariinventors
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Abstract
Method and system for discrete soft handoff of mobile terminals in a wireless CDMA network. Mobile terminal-base station channels perform soft handoff in a discrete fashion by predicting which reserved channels will be “strong” and “weak” for CDMA data frame transmission. At least one of the strong channels is included in the active set of handoff legs used to transmit the CDMA data frame, and the invention transmits the CDMA data frame only through channels within the active set.
Claims20
A method for effecting a soft handoff in a wireless communications network between a mobile terminal and a plurality of base stations wherein there are a plurality of handoff legs reserved for communication between said mobile terminal and said base stations, said method comprising the steps of:
- predicting which of said reserved handoff legs will be a strong channel for the handoff transmission between the mobile terminal and one of said base stations;
- and
- transmitting a wireless communication dataframe over only one or more of said predicted strong channel hand-off legs.
A method for implementing a discrete soft handoff between a mobile terminal and a base station in a wireless telecommunications network, said method comprising the steps of:
- establishing a set of reserved handoff legs for transmitting CDMA data frames between a base station and a mobile terminal;
- measuring the signal strengths of signals in each handoff leg;
- predicting the signal strengths of signals for each handoff leg based on said measured signal strengths;
- and
- determining that at least one of the handoff legs should be an active handoff leg, said active handoff leg meeting a threshold signal strength level as determined based upon said predicting step;
- and
- transmitting the CDMA dataframes from the mobile terminal to the base station over said active handoff leg.
A method for effecting a soft handoff in a wireless communication network comprising mobile terminals, base terminals, and a mobile switching center, said method comprising the steps of:
- a mobile terminal measuring signal attributes of reserved handoff legs in the network,
- the mobile terminal, based on the measured signal attributes, predicting which of the handoff legs will be a strong handoff leg and placing at least one predicted strong handoff leg in a set of reserved active handoff legs;
- the mobile terminal communicating to the mobile switching center the identity of the set of reserved active handoff legs and receiving CDMA data frames communicated from the mobile switching center;
- and
- the mobile terminal creating the best CDMA dataframe from redundant CDMA data frames received from the mobile switching center.
A method for effecting soft handoff in a wireless communication network comprising mobile terminals, base stations, and a mobile switching center, said method comprising the steps of:
- a mobile terminal measuring signal attributes of reserved handoff legs in the network;
- the mobile terminal communicating the collected signal attributes to the mobile switching center;
- the mobile switching center, based on the measured signal attributes, predicting which of the reserved handoff legs will be a strong handoff leg and placing at least one predicted strong handoff leg in a set of reserved active handoff legs;
- the mobile switching center communicating to the mobile terminal CDMA dataframes over the handoff leg in the active set;
- and
- the mobile terminal creating the best CDMA dataframe from redundant CDMA dataframes received from the mobile switching center.
Dependencies are inferred from the claim text.