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Device-to-Device Communication as an Underlay to LTE-Advanced Networks. Doppler, K.; Rinne , M.; Wijting , C.; Ribeiro , C.; Hugl , K.; IEEE Communication Magazine, Vol. 47, No. 12, December 2009 Speaker: Tsung -Han Chiang Date: March 9, 2012. Introduction.
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Device-to-Device Communication as an Underlay to LTE-Advanced Networks Doppler, K.; Rinne, M.; Wijting, C.; Ribeiro, C.; Hugl, K.; IEEE Communication Magazine, Vol. 47, No. 12, December 2009 Speaker: Tsung-Han Chiang Date: March 9, 2012
Introduction • The authors outline a solution for a D2D session setup using dedicated signaling and automatic handover of network routed traffic to D2D links between nearby (proximity) devices.
D2D Session Setup by Detecting D2D Traffic • The session setup requires the following steps: • A session is initiated by one of the UE units. • The gateway detects IP traffic originating from and destined to UE in the same subnet and to be tunneled within the same serving eNB or between eNBs serving neighboring cells. • If the traffic fulfills certain criteria (e.g., data rate), the gateway earmarks the traffic as potential D2D traffic. • The eNB(s) request measurement from the UE to check if D2D communication offers higher throughput • If both UE units are D2D capable and D2D Communication offers higher throughput, the eNB(s) may set up a D2D bearer. • Even if the D2D connection setup is successful, the eNB(s) still maintain the SAE bearer between the UE and the gateway for cellular communications.
D2D Session Setup by Detecting D2D Traffic • Furthermore, the eNB maintains the radio resource control for both cellular and D2D communication. • The UE will send/receive packets to/from the IP address of the peer UE using the D2D connection without the eNB or SAR being involved in routing.
D2D Session Setup by Detecting D2D Traffic • The decision to establish a D2D connection can be based on a defined policy such as limiting the number of D2D connections to keep the interference to the cellular network below a tolerable level. • A handover from a D2D connection to a cellular connection is initiated when the cellular connection achieves higher throughput than the D2D or if one of the policies for D2D connections is violated.
D2D Session Setup Using Dedicated SAE Signaling • A session setup using dedicated SAE signaling avoids the overhead from detecting D2D traffic on the fly from IP packets. • The new address format of D2D SIP could simply be username@realm.D2D_keyword.
D2D Session Setup Using Dedicated SAE Signaling • The authors propose to encapsulate the SIP invite message in an NAS control plan message.
Conclusion • Throughput vs. Interference • Orthogonal frequency • Power Control • Others