Method and device in over-the-air test environment

A test chamber comprising apparatus for providing a simulated radio channel having a defined characteristic between a first device and a second device in a test environment, wherein the apparatus comprises:

• a first antenna configured to receive a first signal and to provide a first radio channel between the first antenna and the second device;
• a second antenna configured to receive a second signal and to provide a second radio channel between the second antenna and the second device, wherein a characteristic of the second radio channel is dissimilar to a characteristic of the first radio channel;
• a modifying circuit configured to modify a relation between the first signal and the second signal to produce signals with a modified relation therebetween;
• a combining circuit configured to combine the produced signals to produce a combined signal, and to forward the combined signal to the first device, thereby providing the simulated radio channel between the first device and the second device, the simulated radio channel having a characteristic that combines, in a relation corresponding to the modified relation, the characteristic of the second radio channel and the characteristic of the first radio channel;
• and
• a delay circuit comprising:
• an input configured to receive at least part of at least one of the first signal and the second signal;
• a delay configured to delay the received at least part of the at least one of the first signal and the second signal to produce a delayed output signal;
• and
• an output configured to forward the delayed output signal towards the first device,
• wherein the input is further configured to receive at least part of the forwarded delayed output signal;
• wherein the delay is further configured to delay the received at least part of the forwarded delayed output signal to produce a further delayed output signal;
• and
• wherein the output is further configured to forward the further delayed output signal toward the first device.

A method of providing a simulated radio channel having a defined characteristic between a first device and a second device in a test environment, wherein the method comprises:

• receiving a first signal on a first antenna, the first antenna providing a first radio channel between the first antenna and the second device;
• receiving a second signal on as second antenna, the second antenna providing a second radio channel between the second antenna and the second device, wherein a characteristic of the second radio channel is dissimilar to a characteristic of the first radio channel;
• modifying relation between the first signal and the second signal to produce signals with a modified relation therebetween;
• combining the produced signals to produce a combined signal;
• forwarding the combined signal to the first device, thereby providing the simulated radio channel between the first device and the second device, the simulated radio channel having a characteristic that combines, in a relation corresponding to the modified relation, the characteristic of the second radio channel and the characteristic of the first radio channel;
• receiving, at an input of a delay circuit, at least part of at least one of the first signal and the second signal;
• delaying, in a delay of the delay circuit, the received at least part of the at least one of the first signal and the second signal to produce a delayed output signal;
• forwarding the delayed output signal to the first device via an output of the delay circuit;
• receiving, at the input, at least part of the forwarded delayed signal;
• delaying, in the delay, the received at least part of the forwarded delayed signal to produce a further delayed signal;
• and
• forwarding the further delayed signal to the first device via the output of the delay circuit.