A deterministic queue automaton (DQA) is like a PDA except the stack is replaced by a queue. A queue is a tape allowing symbols to be written (push) on the left-end and read (pull) on the right-end.
Actually I've proved that a 2-tape Turing Machine can simulate the DQA. Now I'm proving the DQA can simulate Turing Machine TM. Let the queue store all the input and the right-end symbol is the one being read. Suppose $a$ is the right-end symbol in the queue.
For the transition $\delta(q,a)=(r,b,L)$ in TM, it's easy to simulate. Just pull $a$ and push $b$. Now the right-end symbol would be the symbol on the left of $a$. It's like move the head in TM to the left.
My problem is I cannot find a way to simulate the transition $\delta(q,a)=(r,b,R)$. Since the symbol on the right of $a$ is actually the left-end symbol, how can I let this symbol move to the right-end? I spend several hours on this and I think answers on Internet are not very clear. Could anyone give me some hint?