--- title: "Numerical: cellular vs non-cellular voice channels" subject: "Wireless Communication" chapter: 2 key: "semester_7/wireless_communication:cellular-vs-noncellular-channels" source: https://www.bctengineer.com/q/semester_7/wireless_communication/cellular-vs-noncellular-channels site: BCT Engineering --- # Numerical: cellular vs non-cellular voice channels Wireless Communication · Chapter 2: Cellular Mobile Communication Concepts - Asked in: 2082 Baisakh, 1+3 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/wireless_communication/cellular-vs-noncellular-channels - Whole chapter: https://www.bctengineer.com/md/semester_7/wireless_communication/chapter-2 ## Question Consider a single high-power transmitter that can support 40 voice channels over an area of 140 km² with the available spectrum. If this area is equally divided into seven smaller cells, each supported by lower power transmitters so that each cell supports 30% of the total voice channels, then determine i) Coverage area of each cell [1] ii) Total number of voice channels available in a cellular system compared to a non-cellular system. [3] ## Short answer Coverage area per cell is 140 km² divided by 7, giving 20 km². Each cell reuses 30% of the 40 voice channels, i.e. 12 channels; total cellular channels = 7 × 12 = 84, versus 40 in non-cellular, a 2.1× capacity increase from frequency reuse. ## Answer **Given:** single high-power transmitter: 40 voice channels over 140 km². Area divided into 7 equal cells; each cell supports 30 % of total channels. #### i) Coverage area of each cell ```text A_cell = 140 / 7 = 20 km² ``` #### ii) Total voice channels: cellular vs non-cellular Channels per cell: ```text k = 30 % of 40 = 0.3 × 40 = 12 channels per cell ``` Total channels in the cellular system (each cell uses its own 12 channels; channels are reused in non-adjacent cells): ```text C_cellular = 7 × 12 = 84 channels ``` Non-cellular system: ```text C_non-cellular = 40 channels ``` Ratio: ```text 84 / 40 = 2.1 ``` **Answer: (i) 20 km² per cell; (ii) the cellular system provides 84 channels versus 40, i.e. 44 more channels or 2.1 times the capacity, because frequencies are reused in different cells.** ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Dividing 140 km^2 into 7 equal cells gives each cell a coverage area of: A. 980 km^2 B. 20 km^2 C. 10 km^2 D. 28 km^2 Answer: B. A = 140/7 = 20 km^2. (Key point: Area per cell) 2. Each cell supports 30% of the 40 total channels. How many channels does each cell have? A. 30 B. 7 C. 28 D. 12 Answer: D. 0.3 x 40 = 12 channels per cell. (Key point: Channels per cell) 3. What is the total number of channels in the 7-cell system? A. 84 B. 40 C. 12 D. 280 Answer: A. 7 cells x 12 channels = 84 channels, because channels are reused in different cells. (Key point: Total cellular capacity) 4. Why does the cellular system provide 84 channels against 40 for the single transmitter? A. Each low-power transmitter uses extra spectrum B. The cells are larger than the original area C. Frequencies are reused in different cells of low-power transmitters D. The 40 channels are replaced by wider channels Answer: C. Low power lets the same channels be reused in non-adjacent cells, giving 2.1 times the capacity. (Key point: Why capacity increases) ## Related in Wireless Communication - [Numerical: 32-cell system area and channels](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Acellular-32-cells-capacity) — Wireless Communication, chapter 2 - [Non-linear effect in FDMA; channels numerical](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Afdma-nonlinear-channels) — Wireless Communication, chapter 7 - [Spread spectrum and DSSS transmitter/receiver](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Aspread-spectrum-dsss-tx-rx) — Wireless Communication, chapter 4 - [Numerical: FDMA channels (12.8 MHz)](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Afdma-channels-12-8mhz) — Wireless Communication, chapter 7, asked 2× - [Numerical: trunked channels and blocking (Erlang B)](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Atrunking-five-channel-blocking) — Wireless Communication, chapter 2 - [Numerical: FDMA channels (12.5 MHz)](https://www.bctengineer.com/question.md?key=semester_7%2Fwireless_communication%3Afdma-channels-12-5mhz) — Wireless Communication, chapter 7 ## Related in other subjects - [FDM bandwidth for 10 voice channels](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Afdm-10-voice-channels) — Data Communication, chapter 6 - [Receiving end power, 140.2∠18.2° kV and 132 kV](https://www.bctengineer.com/question.md?key=semester_4%2Fpower_system_analysis_i%3Areceiving-power-140-2kv) — Power System Analysis I, chapter 6 - [Smaller area bounded by circle and line](https://www.bctengineer.com/question.md?key=semester_2%2Fmathematics%3Asmaller-area-bounded-circle-line) — Mathematics, chapter 2 - [IP telephony / Voice over IP](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Aip-telephony-voip) — Telecommunications, chapter 8, asked 4×