MC và các hệ thống phổ Bá P6
Additional Techniques for Capacity and Flexibility Enhancement
As shown in Chapter 1, wireless channels suffer from attenuation due to the destructive addition of multipath propagation paths and interference. Severe attenuation makes it difficult for the receiver to detect the transmitted signal unless some additional, lessattenuated replica of the transmitted signal are provided. This principle is called diversity and it is the most important factor in achieving reliable communications. Examples of diversity techniques are: — Time diversity: Time interleaving in combination with channel coding provides replicas of the transmitted signal in the form of redundancy in the temporal domain to the receiver....