名词解释1．Explain the difference between hard and soft handoff.Answers：The hard handoff is that when the signal strength of a neighboring cell exceeds that of the current cell, plus a threshold, the mobile station is instructed to switch to a new frequency band that is within the allocation of the new cell.The soft handoff is that a mobile station is temporarily connected to more than one base station simultaneously. A mobile unit may start out assigned to a single cell. If the unit enters a region in which the transmissions from two base stations are comparable, the mobile unit enters the soft handoff state until which it is connected to the two base stations.2．What are the cores techniques of WCDMA?Answers: The WCDMA key techniques mostly consist of the power control technique, PN code technique, RSKE, Soft Handoff, and Speech coding.3．What is attenuation?4．What two functions are performed by an antenna?5．What are the advantages of using CDMA for a cellular network?Answers: (1)Frequency diversity; (2) Multipath resistance; (3) Privacy; (4) Gracefue degradation.6. What are the key differences between first and second generation cellular system?Answers: The key differences between the two generations: (1). Digital traffic channels; (2). Encryption; (3). Error detection correction; (4). Channel access.7. What are the cores techniques of TD-SCDMA?Answers: The cores techniques of TD-SCDMA are smart antenna (intelligent antenna), joint examination technique, SCDMA technique, software wireless technique, and dynamic channel allocation technique8. What is direct broadcast satellite (DBS)?Answers: The satellite video signals are transmission directly to the home user.9. What is an isotropic antenna?Answers: An isotro...
