Abstract: Disclosed is a method for encrypted communications. A first IPsec endpoint selects a security association (SA) from a security association database (SAD) by using a selector and then extracts an indexing parameter from SA. The indexing parameter is used to determine an active key location from a key storage database (KSD). Data packets are then encrypted using a key from the active key location. The first IPsec endpoint also forms a security parameter index (SPI) in a header of the data packet by using a keyID from the active key location and transmits the encrypted data packet with the header indicating the SPI to a second IPsec endpoint.

Abstract: A method and system of accessing a de-keyed base station is disclosed. The method and system comprise de-keying a base station in a conventional TDMA communications system and starting a timer in the base station when the base station de-keys. The method and system further comprise receiving a transmission from a mobile station and re-keying and repeating the transmission, if the transmission is received with proper synchronization before expiration of the timer.

Abstract: Roaming encryption key rekeying apparatus and method comprising a first system key management facility that communicates to a communication unit roaming information is disclosed. The roaming information is encrypted using a first encryption scheme that is decipherable by the communication unit. Further, the first system key management facility communicates to a second system key management facility the roaming information. In this communication, the roaming information is encrypted as a function of a second encryption scheme that is decipherable by the second system key management facility.

Abstract: A method and system for scanning a TDMA channel by a subscriber unit in a wireless communications landscape 100 is disclosed. The subscriber unit locks onto a channel that is preprogrammed in the subscriber unit. A base radio transmits a control message to the subscriber unit. The control message informs the subscriber unit of activity present on the channel. The subscriber unit receives and decodes the control message to determine whether there is activity on the channel. If there is, the subscriber unit determines whether the activity is of interest. If it is, then the subscriber unit remains on the channel to receive the activity present on the channel.

Abstract: In a TDMA system whereby the TDMA system comprises a plurality of subscriber units and a plurality of base radios, a method and system for providing access to a channel for voice transmissions where the first subscriber unit determines whether it is provisioned for polite access to the channel. In addition, the first subscriber unit is characterized by a first color code and a first talkgroup ID. The first subscriber unit also examines the voice transmissions on the channel for voice transmissions that are from a second subscriber unit with a second color code and a second talkgroup ID. If the first color code and the second color code match and if the first talkgroup ID and the second talkgroup match, then the first subscriber unit is allowed access to the channel for voice transmissions even though the channel is being used for voice transmissions by the second subscriber unit.