N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 9 - Wireless Systems and Technologies                                                                                 Slide 58 of 80                                                                                                    ________________ 

                                            WLL Systems

                                    Digital and Analogue Cellular

                                    Cordless

                                    Proprietary

                                                                                                   ________________

WLL systems fall into three categories: Digital and Analogue Cellular Systems, Cordless Systems and Proprietary Systems

Digital and Analogue Systems - These WLL systems are cellular systems with limited mobility. Fixed Cellular systems have excellent range and are ideal for serving low-density to medium-density areas where the main goal is to provide basic voice services without extra features. The quality of service is well below wire-line and data transfer is limited to 9.6 K bps.

Cordless Systems - These systems were developed to provide service within a home or business. Cordless WLL systems are more suited for medium-density to high-density areas. These systems offer a high level of scalability and functionality. The cordless systems can carry a higher level of traffic, deliver higher quality of voice services and support higher data rates than the cellular systems. The cordless systems use 32 k bps ADPCM compression standard for voice. The cordless system standards are DECT and PHS.

Proprietary Systems -This category includes fixed wireless systems such as LMDS and MMDS. LMDS operates at 24 - 40 G HZ and can support very high data rates for voice, video and data applications targeted at business.