Due to the evolution of mobile technology and the
emergence of terminals like smart phones, Internet based applications mostly accessed
over the Transmission Control Protocol (TCP) have become dominant on mobile platforms.
However,since the TCP flow control mechanisms were designed for wired environments,
short-term degradations on the air interface of radio access systems may lead to unnecessary
performance drops. TCP freeze is a possible solution to improve such situations by
triggering the persist mode of the TCP sender, preventing TCP timeouts and rate reductions
during poor radio conditions. This paper investigates a network element based implementation
of the TCP freeze mechanism, which has the advantage that it can accurately follow
the radio conditions of the User Equipments (UE) while being completely transparent
to the TCP sender and receiver. The possible performance gain of the solution was
investigated by simulating a network with coverage holes. Results indicate that the
network side freeze can considerably reduce the time the TCP connections spend in
outage and thus it can increase the responsivity and data throughput provided by the
system.
