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An emerging trend in mobile communications is the parallel usage of multiple radio technologies in mobile devices, tablets and other communications modules. In order to support this parallel operation, the devices are equipped with multiple radio transceivers, which are located extremely close to each other. When the different radio technologies operate simultaneously these transceivers interfere with each other resulting in in-device coexistence (IDC) interference. This article describes the IDC interference problem involving LTE (Band 7) and WLAN (2.4 GHz) technology and evaluates the performance of two different mitigation techniques used to reduce the interference effect.
With the increasing demand to have ubiquitous and seamless data connectivity Y Y to several wireless networks, modem day devices are designed to support different radio access technologies (RAT). These devices, e.g., mobile phones, tablets and various other communications modules are capable of supporting different cellular as well as non-cellular communications standards at the same time. For instance, a mobile phone might be connected to a wireless local area network (WLAN)1 router for Internet access in parallel to an established long term evolution (LTE)2 call.
Due to the small size of these devices, the transceivers of different radio technologies are located very close to each other. As a result, when these collocated radio transceivers operate concurrently in the same or adjacent frequency bands, it leads to potential interference between their operations known as in-device coexistence interference. IDC interference affects the receiver sensitivity, thereby degrading the quality of the wanted signal or resulting in the loss of data.
This article discusses the challenge of reducing IDC interference while multiple RATs are operating simultaneously. Reducing IDC interference would prevent degradation of the signal quality without disconnecting the interfering radio signal. The article highlights the coexistence scenario between LTE and WLAN, where LTE Band 7 uplink affects the WLAN 2.4 GHz channels, and discusses possible solutions to mitigate IDC interference. First, the cause of IDC interference is described then the different frequency bands where IDC interference occurs are considered, along with the different RATs involved.
Next, the methodology for calculating the desensitization value is discussed, including a description of a possible test setup required to carry out the measurements. After that, it analyzes the use of two different mitigation techniques in...