【In the forthcoming years,Beyond-3G(B3G)environments will undoubtedly be deployed in most parts aroundthe  globe,permitting a world class solution for network intetconneciton,A B3G context enables the efficient cooperation of existhing wireless technologies,including cellular-based(e.g 2G/3G),broadcast-oriented (e.g. DVB)-in  specific DVB-H,and Internet-based(WLAN/WMAN)networks,all relying on enhanced IP as the unifying layer. Hence,in this particular and yet to be deployed environment,mobile,systems and platforms will permit to provide enhanced services to all applications across heterogeneous access networks.This will effectively enlarge the scope of service deployment,availability and accessibility to the users】
  Based on the paragraph above,it is shown that（1） will be used as the higher layer protocol to unify cellular networks,broadcast networks and（2）networks,which is enabled by the context of（3）.
(1)
A.mobile systems and platforms   
B.3G
C.heterogeneous access networks   
D.enhanced IP
(2)
A.Internet-based   
B.WLAN    
C.WMAN       
D.B3G
(3)
A.IP network   
B.B3G    
C.internet     
D.deployed environment