With the advent of machine-to-machine communications, various networking consumer industrial, and autonomous systems exchange messages in the real world in order to achieve their objectives. Parts of these systems are comprised of short-range wireless networks in the form of clusters that collectively cover a large geographical area. In these clusters, the nodes that represent the cluster heads need to deal with two types of communications, ie, one is within the cluster and the other is from the cluster to the sink node. As the number of clusters increases, it takes multiple hops for the cluster head to forward data to the sink node, thus resulting in a low packet delivery rate (PDR) and throughput. To solve this problem, we propose a heterogeneous area network in which the cluster head is equipped with two types of radios, ie, the IEEE 802.15.4 and IEEE 802.11 radios. The former is for the devices within the cluster to communicate, whereas the latter is for the cluster heads to communicate to the sink node. Although the IEEE 802.11 links increase the link capacity, the IEEE 802.11 radio and the IEEE 802.15.4 radio might share the 2.4 GHz unlicensed band, thus giving rise to the internetwork collisions or interference. To tackle this problem and to maintain decent quality of service for the network, we subsequently present two interference mitigation techniques, in which a blank burst period is proposed so that the IEEE 802.15.4 radios can be suspended while the IEEE 802.11 radios are active.Simulation results show the proposed two methods can effectively mitigate the internetwork collisions and are superior to the existing technique, which uses an adaptive aggregation technique to mitigate the internetwork collisions. This is because the accumulated traffic is beyond the capacity of the relay cluster heads, thus resulting in buffer overflow and the significant performance degradation of the WSN.To tackle this issue, we connect the cluster head to an IEEE 802.11 (ie, Wi-Fi) node to form a heterogeneous area network. The IEEE 802.11 standard can be characterized as a high data rate and high throughput specification, which is good compensation for the shortcomings of IEEE 802.15.4 networks. In this work, we adopt IPv6 over low-power wireless personal area network (6LoWPAN) networks as the networks based on the IEEE 802.15.4 standard. In the proposed heterogeneous area network, the IEEE 802.11 network serves as the backbone network connecting the cluster heads and the sink node. More specifically, IEEE 802.11 networks have a higher transmission rate up to 400 Mbps (eg, IEEE 802.11n) and a much longer transmission range up to 300 meters compared to 6LoWPAN networks. As a result, these two advantages can help the 6LoWPAN networks handle a large amount of traffic over a large-scale area. It is noted that both the two networks share the unlicensed 2.4 GHz band, so the relatively high transmission power of the IEEE 802.11 network can adversely affect the transmissions of the 6LoWPAN network and cause internetwork collisi...