Help please

Question B3 (a) Give two reasons why networks might use an error correcting code instead (b) The Bluetooth (IEEE 802.15) physical radio layer uses frequency hopping of error detection and retransmission. (4 marks) spread spectrum. Discuss the need for and technical operation of this protocol. List two Upper layer Bluetooth applications (8 marks) (c) 802.16 (WiMax broadband wireless) and 802.11 (WiFi) both facilitate Internet access. Explain why two separate protocols evolved and critically evaluate their advantages and disadvantages. (8 marks)