Many employers suspend employees whilst an allegation is being investigated. The reason is that it can make the atmosphere at work difficult if the accused and accuser are sharing the same space and it makes it easier to investigate allegations.
As such the decision to suspend an employee is usually considered a reasonable one and would not give grounds to sue however distressing it is to be suspended.
The only way that you could sue is if you can show that the suspension itself was totally unreasonable or was done out of spite in a situation where it was not warranted.
I hope this helps. If there are any further points please reply