### Advantages of M-ary signalling – summary #### A higher information transfer rate is possible for a given symbol rate and corresponding channel bandwidth, #### or #### A lower symbol rate can be obtained, leading to a reduced bandwidth requirement for a given information transfer rate. (Both result in an increase of bandwidth efficiency – bits/second/Hz)
### Disadvantages of M-ary signalling – summary #### M-ary baseband signalling results in reduced noise/interference immunity when compared with binary signalling (see Section 3.5), as it becomes more and more difficult to distinguish between symbol states. #### It involves more complex symbol recovery processing in the receiver. #### It imposes a greater requirement for linearity and/or reduced distortion in the TX/RX hardware and in the channel (except for orthogonal M-FSK).