Sprint Spectrum L.p.

Christopher R Melus

Lyle Thomas Bertz

William James Routt

Ronald E Lewis

Ihab Amin Guirguis

Nagi A Mansour

Emerino J Marchetti

An Internet Protocol Multimedia Subsystem (IMS) network uses the Session Initiation Protocol (SIP) to provide communication services to mobile nodes. A short message service gateway (SMS-GW) in the IMS network receives a request to deliver a message to a mobile node. The SMS-GW determines whether the mobile node is IMS registered. If the mobile node is IMS registered, the SMS-GW may transmit a SIP MESSAGE request to a call session control function (CSCF) serving the mobile node in order to deliver the message to the mobile node. If the mobile node is SIP-capable but is not IMS registered, the SMS-GW may instead transmit a SIP MESSAGE request to the mobile node's IP address. To obtain the mobile node's IP address, the SMS-GW may query a domain name server (DNS) that stores associations between hostnames and IP addresses of mobile nodes.

Method and system for delivering short message service (SMS) messages using the session initiation protocol (SIP)

Reference signals (a.k.a., pilot signals) are broadcast to aid in at least channel estimation, cell selection, and handover. When a multi-antenna mode (i.e., MIMO) is used data signals on one antenna should not interfere with reference signals on another antenna. Reference signal resource elements (a.k.a., slots) being broadcast from one antenna are multiplied by a first Walsh code and the data (or reference) signal resource elements being broadcast from another antenna are multiplied by second Walsh code in the same family. Multiplication by Walsh codes reduces or eliminates the correlation between the data resource elements on a first antenna and the reference signal resource elements simultaneously broadcast on a second antenna.

Utilization of MIMO reference signal resource blocks

An application server provides communication services via a packet-switched network to mobile nodes based on their respective registrations in a registry, such as a home subscriber server (HSS) or domain name server (DNS). A registration proxy may be used to effect a registration in the registry on behalf of a mobile node when the mobile node lacks sufficient capability to effect the registration itself. The registration proxy may perform this function after receiving a notification that the mobile node is connected to the packet-switched network and after querying a capabilities server to determine that the mobile node lacks sufficient registration capability. To effect a registration in an HSS, the registration proxy may emulate either a serving call state control function (S-CSCF) or user equipment (UE).

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Brambleton, VA, United States of America

Christopher R Melus