A network system for coexistence of a Wi-Fi HaLow network and a low-rate wireless personal area network, LR-WPAN, comprising: a receiver for receiving a wireless signal over a frequency band shared with the LR-WPAN using an LR-WPAN protocol; a detector for detecting an energy level of the wireless signal; a memory storing a first program for performing an energy-detection, ED, clear channel assignment, CCA, control process; a processor, in connection with the detector and the memory, for executing the first program to determine if a transmission of a packet is permitted based on the detected energy level of the wireless signal according to the ED CCA control process, wherein the ED CCA control process determines a first ED threshold between a receiver sensitivity, RS, of an LR-WPAN protocol and a second energy-detection, ED, threshold of the Wi-Fi HaLow protocol, wherein the ED CCA control process permits the transmission when the detected energy level of the wireless signal is less than the first ED threshold; and a transmitter for transmitting the packet over the frequency band according to a Wi-Fi HaLow protocol when the ED CCA control process has permitted the transmission; wherein the ED CCA control process does not permit the transmission when the detected energy level of the wireless signal is greater than the second ED threshold; wherein when the detected energy level of the wireless signal is greater than the first ED threshold but less than the second ED threshold, the ED CCA control process determines if the transmission is permitted according to a computation result of an optimal α-fairness solution of a predetermined object function, wherein the predetermined objective function is expressed by V P 1 P 2 = 1 1 − α P 1 1 − α U 1 1 − α U 1 1 − α + U 2 1 − α + P 2 1 − α U 2 1 − α U 1 1 − α + U 2 1 − α P i ≥ 0, i = 1,2, α > 0, α ≠ 1 wherein P 1 + P 2 = 1, P 1 is a permissible probability of the transmission, P 2 is an impermissible probability of the transmission, α is a parameter to control fair channel access allocation between the Wi-Fi HaLow network and the LR-WPAN, U 1 and U 2 are network utilities of the Wi-Fi HaLow network and the LR-WPAN, respectively. a receiver for receiving a wireless signal over a frequency band shared with the LR-WPAN using an LR-WPAN protocol; a detector for detecting an energy level of the wireless signal; a memory storing a first program for performing an energy-detection, ED, clear channel assignment, CCA, control process; a processor, in connection with the detector and the memory, for executing the first program to determine if a transmission of a packet is permitted based on the detected energy level of the wireless signal according to the ED CCA control process, wherein the ED CCA control process determines a first ED threshold between a receiver sensitivity, RS, of an LR-WPAN protocol and a second energy-detection, ED, threshold of the Wi-Fi HaLow protocol, wherein the ED CCA control process permits the transmission when the detected energy level of the wireless signal is less than the first ED threshold; and a transmitter for transmitting the packet over the frequency band according to a Wi-Fi HaLow protocol when the ED CCA control process has permitted the transmission; wherein the ED CCA control process does not permit the transmission when the detected energy level of the wireless signal is greater than the second ED threshold; wherein when the detected energy level of the wireless signal is greater than the first ED threshold but less than the second ED threshold, the ED CCA control process determines if the transmission is permitted according to a computation result of an optimal α-fairness solution of a predetermined object function, wherein the predetermined objective function is expressed by V P 1 P 2 = 1 1 − α P 1 1 − α U 1 1 − α U 1 1 − α + U 2 1 − α + P 2 1 − α U 2 1 − α U 1 1 − α + U 2 1 − α P i ≥ 0, i = 1,2, α > 0, α ≠ 1 wherein P 1 + P 2 = 1, P 1 is a permissible probability of the transmission, P 2 is an impermissible probability of the transmission, α is a parameter to control fair channel access allocation between the Wi-Fi HaLow network and the LR-WPAN, U 1 and U 2 are network utilities of the Wi-Fi HaLow network and the LR-WPAN, respectively.